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New diesel water heater


RickS

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5 minutes ago, Rick Savery said:

Thanks to all who have replied with their help and advice. I think I shall be going down the Eberspacher route.

 

Sorry to crowbar this into this thread, but can the diesel heater be used to heat the hot water tank without heating the radiators? In the Summer obviously won't be needing the rads but is running the engine the only way to get hot water? I was just wondering what happens when you are moored up for a few days

 

Thanks again

 

My system has 1 rad that you can't turn off (for safety reasons), the rest are on thermo valves and get turned off in the summer.

I was told recently by a marine engineer that he got called to a boat with a failed Eberspacher.  It turn out to be an empty diesel tank.  The owner had no idea about the need for diesel, he thought it ran on batteries because he could hear the fan running all the time. 

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33 minutes ago, Rick Savery said:

Thanks to all who have replied with their help and advice. I think I shall be going down the Eberspacher route.

 

Sorry to crowbar this into this thread, but can the diesel heater be used to heat the hot water tank without heating the radiators? In the Summer obviously won't be needing the rads but is running the engine the only way to get hot water? I was just wondering what happens when you are moored up for a few days

 

Thanks again

Yes. You'll need a valve (manual or motorised) to turn off the radiators, unless they all have thermostatic valves on them.

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2 hours ago, Rick Savery said:

Thanks to all who have replied with their help and advice. I think I shall be going down the Eberspacher route.

 

Sorry to crowbar this into this thread, but can the diesel heater be used to heat the hot water tank without heating the radiators? In the Summer obviously won't be needing the rads but is running the engine the only way to get hot water? I was just wondering what happens when you are moored up for a few days

 

Thanks again

I've already answered this as a yes above Rick? Isolation valve to the heating circuit. Endorsed by Espar

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Thanks again all. Markinaboat, I'm afraid a lot of the technical info went above my head so if you did answer that I failed to see it, but I'm sure you did, and thank you.

 

Presumably the one radiator left on for safety would be as a sort of pressure relief? If I shut off the rads and fire up the diesel heater would it not start to heat the radiator system via the hot water tank anyway? You can tell i know sod all about these systems!

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23 minutes ago, Rick Savery said:

Thanks again all. Markinaboat, I'm afraid a lot of the technical info went above my head so if you did answer that I failed to see it, but I'm sure you did, and thank you.

 

Presumably the one radiator left on for safety would be as a sort of pressure relief? If I shut off the rads and fire up the diesel heater would it not start to heat the radiator system via the hot water tank anyway? You can tell i know sod all about these systems!

you don't need to leave a radiator on for safety. Just heat the calorifier. When the water's hot enough, the HS3 will cycle down to 1.3kw. Speak to the suppliers and you'll have all of the info!

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I have been reading the Eberspacher literature and the whole short cycling aspect of using the heater is starting sink in (I think).

I understand turning off the radiators in summer and best use of the heater to just heat water is to heat the calorifier then turn off the heater to avoid cycling.

What I'm struggling a bit with is having a radiator or towel rail without a turnoff valve to create a larger circuit and is kept on during summer (is that right?) and the whole process of regulating the flow, with a valve. the regulating I presume i can learn or maybe that is set initially and then left? But the towel rail as a larger circuit I'm not sure about.

I think this was spoken about earlier - the first radiator in the system is in the bedroom - I don't see how, if the heating circuit is turned off in summer, anything other than the first one can be used in this way - but, as I say, I'm struggling with it.

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Essentially a pumped system normally has all its radiators in parallel to the boiler out and return pipe. If you T the out and return between the heater and the  single valve that you will use to isolate the rest of the radiators then as far as the boiler is concerned the Ts are just another radiator. Hot water can not to and from the Ts but the shut of valve prevents it reaching the other radiators.

 

This does not address the balancing of the system where you adjust the valves on the individual radiators to optimise the water flow through each radiator (and the Ts)

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You're all very rude about Mikunis.  The Mikuni MX40 which was fitted to Theodora is still going strong 14 years after buying the boat.  It displayed aberrant behaviour when we first got it but it has performed well after I did a bit of diy serviceing on it.  Twice I have had the problem of it refusing to start but a quick rub over the photo transistor for sorted that.  I have had almost no trouble with the glowplug coking up and when I have a quick rub over with a wire brush sorted it out.  The trick with the glowplug is to make sure that the littel hole at the boss end is plroberly clear.

 

I have found it very good doing the job for which is was designed: it preheats my BMC 1.5 nicely.

 

Nick

 

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On 22/03/2021 at 12:07, Jackofalltrades said:

However, the jet engine noise the damn thing makes is something I'll never get used to

Does everybody else have a jet engine in their Webasto ThermoTop C?  I don't seem to have one.  Have I been short-changed by my installer?

On 22/03/2021 at 12:07, Jackofalltrades said:

However, the jet engine noise the damn thing makes is something I'll never get used to

Does everybody else have a jet engine in their Webasto ThermoTop C?  I don't seem to have one.  Have I been short-changed by my installer?

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8 minutes ago, system 4-50 said:

Does everybody else have a jet engine in their Webasto ThermoTop C?  I don't seem to have one.  Have I been short-changed by my installer?

Does everybody else have a jet engine in their Webasto ThermoTop C?  I don't seem to have one.  Have I been short-changed by my installer?

 

 

Looks like youe been shortchanged twice, I'd ask for my money back, I'd ask for my money back.

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10 minutes ago, system 4-50 said:

Does everybody else have a jet engine in their Webasto ThermoTop C?  I don't seem to have one.  Have I been short-changed by my installer?

Does everybody else have a jet engine in their Webasto ThermoTop C?  I don't seem to have one.  Have I been short-changed by my installer?

Yes, as you have already figured out, I have the twin jet model.

 

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19 hours ago, Tony Brooks said:

Essentially a pumped system normally has all its radiators in parallel to the boiler out and return pipe. If you T the out and return between the heater and the  single valve that you will use to isolate the rest of the radiators then as far as the boiler is concerned the Ts are just another radiator. Hot water can not to and from the Ts but the shut of valve prevents it reaching the other radiators.

 

This does not address the balancing of the system where you adjust the valves on the individual radiators to optimise the water flow through each radiator (and the Ts)

Thanks Tony

I'm not 100% sure what you mean even though I'm sure you expressed it in simple terms - shows my level of knowledge

Rather than try to convey what I understand you to mean in writing, I have drawn it out

image.png.c8cab0392603ff5018f9d690ddb59c6f.png

Is the red line the part of the circuit you mean by connected by Ts? I assume you are referring to T-shape copper joints?

Apologies for appearing so dense but when it comes to plumbing, I'm afraid I am! So the red line would, as you say, be jsut another rad / towel rail to the heater?

I have left out any expansion tanks and ergulator valves for clarity.

I have no idea about the regulation side of it - I know that I will be getting someone else to fit the heater, but I think it's important to have a grasp of whats going on in the boat

Any books / website you recommend to learn more about this please?

Ta

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2 hours ago, Rick Savery said:

Thanks Tony

I'm not 100% sure what you mean even though I'm sure you expressed it in simple terms - shows my level of knowledge

Rather than try to convey what I understand you to mean in writing, I have drawn it out

image.png.c8cab0392603ff5018f9d690ddb59c6f.png

Is the red line the part of the circuit you mean by connected by Ts? I assume you are referring to T-shape copper joints?

Apologies for appearing so dense but when it comes to plumbing, I'm afraid I am! So the red line would, as you say, be jsut another rad / towel rail to the heater?

I have left out any expansion tanks and ergulator valves for clarity.

I have no idea about the regulation side of it - I know that I will be getting someone else to fit the heater, but I think it's important to have a grasp of whats going on in the boat

Any books / website you recommend to learn more about this please?

Ta

The chances are the red would stop the radiators working as the water will take the easiest path, In my system the calorifier is connected across the flow and return just like the radiators but before the valve so closing the valve cuts off the radiators and still allow water to flow through the calorifier. If your system is as shown with the calorifier in series with the radiators then you either need two valves (one as shown and one on the red pipe) or a changeover (threeway) valve which would be positioned where the red pipe joins the radiator circuit.

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29 minutes ago, Detling said:

The chances are the red would stop the radiators working as the water will take the easiest path, In my system the calorifier is connected across the flow and return just like the radiators but before the valve so closing the valve cuts off the radiators and still allow water to flow through the calorifier. If your system is as shown with the calorifier in series with the radiators then you either need two valves (one as shown and one on the red pipe) or a changeover (threeway) valve which would be positioned where the red pipe joins the radiator circuit.

I'm not really saying that's what my system is like as I'm not 100% sure. I'm just trying to understand some basic concepts so when my new heater is isntalled I'll know more what to ask for and what might need changing.

I take your point about water taking the shorter path along the red line and the calorifier installed in front of the red line but similarly to the radiators. Two valves makes sense, if I'm understanding it correctly - the Eberspacher literature show a similar but more detailed diagram that has a regulator valve on the red line - which I don't pretend to understand 

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Yes that is what I mean and no it won't stop the radiators working because they all should be balanced by the valves on each radiator so they all get their share of the flow. It is possible that you might have to fully pen the balance valve on the new (red) section whenever the radiators are shut off and then set it back when you turn the radiators back on.

 

I am assuming the boiler hot outlet pipe is the lower one on the diagram

 

No idea about websites or books but it's only a small "domestic" type central heating systems so look at how house central heating is done.

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1 hour ago, Tony Brooks said:

Yes that is what I mean and no it won't stop the radiators working because they all should be balanced by the valves on each radiator so they all get their share of the flow. It is possible that you might have to fully pen the balance valve on the new (red) section whenever the radiators are shut off and then set it back when you turn the radiators back on.

 

I am assuming the boiler hot outlet pipe is the lower one on the diagram

 

No idea about websites or books but it's only a small "domestic" type central heating systems so look at how house central heating is done.

Actually Tony, I can't lie, I originally drew the heater output as the top line, but thinking about it, that doesn't make sense does it, as it has to go to the calorifier first? So, yes, the bottom line is the output from the heater ? .

When you say that the radiatiors get their share of the flow, would that be as simple (?) as making the furthest one away from the heater open fully, whilst the closer ones are progressively closed down more? I'm not sure what I've just said makes sense as the furthest one still gets its hot water after the radiator 'in front' of it.

Balance valve ? - I am going to have do some more research on that, as I am not clear about what that means or entails

Good point about it being essentially a small domestic system - I can look at non-boat literature

Thanks again

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16 minutes ago, Rick Savery said:

Actually Tony, I can't lie, I originally drew the heater output as the top line, but thinking about it, that doesn't make sense does it, as it has to go to the calorifier first? So, yes, the bottom line is the output from the heater ? .

When you say that the radiatiors get their share of the flow, would that be as simple (?) as making the furthest one away from the heater open fully, whilst the closer ones are progressively closed down more? I'm not sure what I've just said makes sense as the furthest one still gets its hot water after the radiator 'in front' of it.

Balance valve ? - I am going to have do some more research on that, as I am not clear about what that means or entails

Good point about it being essentially a small domestic system - I can look at non-boat literature

Thanks again

 

Look at the radiators in a house. Typically, they will have two valves on each. Often a thermostatic valve and on the other side what is known as a lock shied valve. That is the one that is used to selectively restrict the flow through the radiator. You seem to have grasped the idea of balancing but I doubt one would be fully open. A domestic heating book/site will tell you how to do it.

 

You could leave the pipe work as you thought you drew it but it would take ages for the hot water to warm up because the radiators would be robbing heat before it got to the calorifier.

 

Just to be sure, I have assumed your red line has the heat dump radiator (plus the balancing valve) in it.

 

 

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2 hours ago, Tony Brooks said:

 

Look at the radiators in a house. Typically, they will have two valves on each. Often a thermostatic valve and on the other side what is known as a lock shied valve. That is the one that is used to selectively restrict the flow through the radiator. You seem to have grasped the idea of balancing but I doubt one would be fully open. A domestic heating book/site will tell you how to do it.

 

You could leave the pipe work as you thought you drew it but it would take ages for the hot water to warm up because the radiators would be robbing heat before it got to the calorifier.

 

Just to be sure, I have assumed your red line has the heat dump radiator (plus the balancing valve) in it.

 

 

Balancing valve yes (although I have to read up more on this) but I am assuming when you say heat dump radiator you mean the heater just treats the red line as if there is a radiator on it, or do you mean there should be an actual rad / towel rail there? If so, then I presumably would have to treat the first rad in my system as that heat dump and put shutoff valves between that one and the rest of the rads?

Wish I was a plumber!

Edited by Rick Savery
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8 hours ago, Rick Savery said:

 

image.png.c8cab0392603ff5018f9d690ddb59c6f.png

 

Calorifier would normally be in parallel with the radiators. As drawn (assuming a clockwise circulation) it will get cold water from the radiators.

 

Edited to add diagram from a previous thread ( in your case ignore the back boiler).

image.png

Edited by David Mack
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8 hours ago, Rick Savery said:

Balancing valve yes (although I have to read up more on this) but I am assuming when you say heat dump radiator you mean the heater just treats the red line as if there is a radiator on it, or do you mean there should be an actual rad / towel rail there? If so, then I presumably would have to treat the first rad in my system as that heat dump and put shutoff valves between that one and the rest of the rads?

Wish I was a plumber!

 

I don't know what the heater manufacturer has to say about how much heat the permanently coupled radiator or towel rail needs to dump.  I have just taken your word that the manufacturer recommends one. I very much doubt  a length of pipe can dump enough heat, hence the manufacturer apparently saying use a radiator or towel rail.

 

A calorifier, towel rail, or radiator are just heat dumps as far as the boiler is concerned so I would say the calorifier is the "first" radiator in the system but how you define it is up to you.

 

I agree with David, the calorifier would normally be in parallel with the radiators so the flow through it can be balanced to allow all "radiators" to receive hot water without anything taking the heat first. I assumed you were either following the heater manufacturer's diagrams or had a good reason of your own for drawing it the way you have.

 

The shut-off  valve goes wherever you want in the system as  long as it prevents flow through the heat dumps you don't want to become hot with the valve turned off.

 

Have you actually looked at the manufacturer's installation diagrams?

 

 

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Thanks Tony

I had looked at an installation diagram from Everspacher before I started asking questions about installation, and even thought I understood it! After looking at my drawing and reading the replies to my post, I don't think I did. Looking at Eberspacher's diagram in the light of the posts and your diagram David Mack, thankyou, it makes more sense now.

 

image.png.af5dca784da5aed3d27ca7e31fb1733e.png

 

I was confused slightly by earlier posts, one of which said that they leave a rad/towel rail on and then a subsequent one which said there was no need to. Apologies if I have used those posts slightly out of context. So this would mean I would need to leave some sort of heat dump (rad or towel rail) on even when the other radiators have been valved off ?

 

In your drawing David Mack, there is a red line returning from the coil in the calorifier to the heater - is that essentially doing the same job as the towel rail in the diagram above ?

My system, or so I believe, does not have this heat dump radiator - I suppose to be 100% certain about that I need to know if and where the radiator shut off valves are.

So if I have turned off pressumably present valves to the radiator system, if I want to use the heater to heat a tank of hot water, i have to have a rad left on before the valves whilst it is heating the calorifier? 

Thanks again Tony and David

Edited by Rick Savery
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7 minutes ago, Rick Savery said:

 

In your drawing David Mack, there is a red line returning from the coil in the calorifier to the heater - is that essentially doing the same job as the towel rail in the diagram above ?

 

Not my diagram, just one I found in an earlier thread. But it shows the return from the calorifier to the heater inlet (and crossing the flow from the heater to the radiators). Functionally it's the same as in the diagram you have just posted.

 

You diagram shows Summer Closeoff Valves which would close off the radiator circuit but leave the towel rail (and calorifier) in circuit.

 

In practice you might need an additional valve in the calorifier circuit to restrict the flow through the calorifier so that the radiators see enough hot water to heat the living space.

Edited by David Mack
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14 minutes ago, Rick Savery said:

Thanks Tony

I had looked at an installation diagram from Everspacher before I started asking questions about installation, and even thought I understood it! After looking at my drawing and reading the replies to my post, I don't think I did. Looking at Eberspacher's diagram in the light of the posts and your diagram David Mack, thankyou, it makes more sense now.

 

image.png.af5dca784da5aed3d27ca7e31fb1733e.png

 

I was confused slightly by earlier posts, one of which said that they leave a rad/towel rail on and then a subsequent one which said there was no need to. Apologies if I have used those posts slightly out of context. So this would mean I would need to leave some sort of heat dump (rad or towel rail) on even when the other radiators have been valved off ?

 

In your drawing David Mack, there is a red line returning from the coil in the calorifier to the heater - is that essentially doing the same job as the towel rail in the diagram above ?

My system, or so I believe, does not have this heat dump radiator - I suppose to be 100% certain about that I need to know if and where the radiator shut off valves are.

So if I have turned off pressumably present valves to the radiator system, if I want to use the heater to heat a tank of hot water, i have to have a rad left on before the valves whilst it is heating the calorifier? 

Thanks again Tony and David

 

The problem with these types of heaters is what is known as short cycling. That is where there is not a sufficient heat dump so the heater very quickly brings the water up to temperature and then shuts down, only to fire up again a few minutes lather. This tends to carbon the thing up and cause breakdowns.

 

I am about 90% sure that Eberspacher show the towel rail as a heat dump over and above the calorifier as a way of lengthening the short cycle periods. If you keep and eye on the calorifier temperature and religiously shut the boiler down when the calorifier is hot or the boiler starts cycling I suspect you would not need the extra heat dump but I can't just say that in case you get boiler problems and you try to blame me. So yes, as far as the manufacturer is concerned you do need to leave the towel rail/radiator on when the rest of the heating system is turned off.

 

Note the diagram shows 15mm pipe feeding the calorifier and towel rail. I suspect this is an attempt to force hot water to the other radiators but I agree with David, you may well need balance valves on both those branches. The valves only cost a few pounds each so its just not worth the potential problems to leave them out when doing the installation. Trying to retrofit them to a wet system is messy.

 

Edited by Tony Brooks
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Thanks Tony

I had read somewhere about it being possibly life-shortening for a diesel heater to keep switching on and off, and how it was better to just turn it on, heat up a tank of water then turn it off.

Then only turning it back on when the tank had run out. This sounded sensible and uncomplicated and i thought that this would be the way I would use it.

Sounds like I don't have to worry so much about the heat dump, but I will talk it through with whomever installs it. I'm not that kind of bloke to hold someone accountable for their freely given advice ? - which I am extremely grateful for. If I was paying you and it exploded, well that's another thing ?

I will have to find some domestic plumbing books and read up on balancing - I think I understand it in principle, but not in any great depth.

As I say, it won't be me installing it but I suspect it would be a good thing to have at least a basic knowledge of it - that said, I know very little about the plumbing in my house so that's a bit hypocritical of me ?

Thanks again

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