Radiator valves

[jetzi]

I'm installing 3 new rads and a towel rail driven from my 4.1kW Eberspacher. It also has a coil in my calorifier.

 

Is it correct to connect TRV valves if they are being driven from an Eberspacher? I'm looking at these on eBay (8,54 GBP per set of TRV valve and lock shield... I need 4). Or is it best to connect a plain stop cock?

 

Also, the previous circuit had a big loop of pipe with radiators in parallel off that pipe. The black arrow in the diagram points to what I'm speaking about - is it necessary to connect the hot feed directly back to the Eber like this? I thought maybe it was for in case all the radiators TRVs were off so that the Eber pump has a complete circuit. But the calorifier is "always on" so it doesn't seem necessary, and I should have thought it would work more effectively if there wasn't a short cut for the hot water.

 

 

[mrsmelly]

Dont fit any valves. Run the unit flat out. Adjust heat by use of windows and doors ?

[jetzi]

I'm not sure if you're serious but I'm actually seriously consididering it. I feel like a stop cock on each rad is still warranted so I can turn off and on rooms at will.

 

Another question, while I'm at it I'm going to replace the coolant in my engine (since I will have to drain it to replace the cauliflower anyway). Should I use the same stuff in my central heating system? It's going to be a reasonably large volume so I imagine it will get quite expensive...

[Chewbacka]

11 hours ago, jetzi said:

I'm not sure if you're serious but I'm actually seriously consididering it. I feel like a stop cock on each rad is still warranted so I can turn off and on rooms at will.

 

Another question, while I'm at it I'm going to replace the coolant in my engine (since I will have to drain it to replace the cauliflower anyway). Should I use the same stuff in my central heating system? It's going to be a reasonably large volume so I imagine it will get quite expensive...

It’s normal to only use balance valves on boat radiators (not TRV) and to have a valve to shut off most rads for summer use, but you must have one that is always on.  Have a look at the link below. Though much of this is specifically for Webasto the general stuff about plumbing, fuel supply and exhaust may be of interest for you.

https://www.butlertechnik.com/downloads/Webasto_Thermo_Top_Evo_Marine_Installation_Instruction_Guide_1.pdf

[jetzi]

1 hour ago, Chewbacka said:

you must have one that is always on.

 

Would the calorifier coil (which has no valves) count as the circuit that is always on?

Alternatively, I could just not put a stop valve on the bathroom towel rail, say?

 

Thanks for the link, reading now.

[jpcdriver]

I found this very helpful document on the Eberspacher site:

https://www.eberspacher.com/fileadmin/data/countrysites/EB_UK/pdf_files/info_pdf_ebuk/narrowboat_pdf_ebuk/waterways_findings_281_jn348.pdf.

 

It details what can cause problems and how to guard against short cycling etc. Hope it is of some help.

 

[Tracy D'arth]

The calorifier coil on its own may not be enough of a heat dump. Why not leave the bathroom towel rail without a TRV? 

It is a waste of time thinking about isolating rooms on a boat, with different temperatures. It will all come to the same temperature eventually.

 

Beware of the expansion if using plastic pipe, long lengths tend to grow massively and pop out like snakes across the floor.

[BEngo]

15 minutes ago, jetzi said:

 

Would the calorifier coil (which has no valves) count as the circuit that is always on?

Alternatively, I could just not put a stop valve on the bathroom towel rail, say?

 

Thanks for the link, reading now.

The cauliflower does not count, because once it gets hot it stops absorbing the heat.  The bathroom towel rail will be OK if it is a decent sized one.

N

[David Mack]

Once the cauliflower is up to temperature,if you don't need the radiators on, you would be better turning the heater off.

[Alan de Enfield]

47 minutes ago, jetzi said:

Would the calorifier coil (which has no valves) count as the circuit that is always on?

 

As has been said - NO.

 

Your cauliflower is insulated to prevent heat loss, when it is used in the 'normal way' (ie, as a hot water retaining tank) you want it to stay as hot as possible for as long as possible. That is the exact opposite of what you need to stop your heater cycling.

[jetzi]

Thanks for the help, especially w.r.t. the calorifier not counting as a heat dump. I didn't realise that that was the purpose of the always on radiator. I assumed the purpose of the always on path was to give the pump somewhere to pump the water.

 

It seems rather pointless to have some radiators on while others are off. If it was getting too hot, then wouldn't it be best to turn the Eber off or like @mrsmelly says, open a window?

 

Edit - I'm an idiot, obviously the reason is so that you can still have hot water in Summer while not having radiators on.

Edited April 6, 2021 by jetzi

[Alan de Enfield]

8 minutes ago, jetzi said:

If it was getting too hot, then wouldn't it be best to turn the Eber off

 

 

I just turn the thermostat down (as you would in a domestic heating situation) it works for me.

 

I have said it before (many times) when we get on the boat the eber gets switched on and stays on until we leave the boat.

If we don't need hot water (because we are cruising every day) or it is cold,  then we will switch it offf until we do need it.

[jetzi]

1 minute ago, Alan de Enfield said:

I just turn the thermostat down (as you would in a domestic heating situation) it works for me.

 

I have said it before (many times) when we get on the boat the eber gets switched on and stays on until we leave the boat.

If we don't need hot water (because we are cruising every day) or it is cold,  then we will switch it offf until we do need it.

 

The only controls on my eber is a single pull switch, on/off. If it has a thermostat, I guess it is pre-set to a particular temperature.

[Alan de Enfield]

Just now, jetzi said:

 

The only controls on my eber is a single pull switch, on/off. If it has a thermostat, I guess it is pre-set to a particular temperature.

 

I had one fitted to the 'water' eber on the NB, but on the cruiser, that uses blown air central heating, the thermostat is a standard feature.

[jetzi]

2 hours ago, Tracy D'arth said:

Beware of the expansion if using plastic pipe, long lengths tend to grow massively and pop out like snakes across the floor.

Oh dear, what can be done about this? Use copper?

 

 

  

2 hours ago, jpcdriver said:

I found this very helpful document on the Eberspacher site:

https://www.eberspacher.com/fileadmin/data/countrysites/EB_UK/pdf_files/info_pdf_ebuk/narrowboat_pdf_ebuk/waterways_findings_281_jn348.pdf.

 

It details what can cause problems and how to guard against short cycling etc. Hope it is of some help.

 

This was extremely helpful to read, thank you!

 

My calorifier coil does not have balance valves, and in fact I think this might have been causing the original problem I had with the Eber - with my radiators only getting somewhat warm,

 

I think what I need to do therefore is to fit manual valves to all 4 radiators AND the calorifier circuit which I can use for balancing, and once balanced, ensure that I never switch off the towel rail. The other radiators I can, if I choose to, use the balance valve to turn off in the Summer months to heat only hot water (and towels). However my expectation is that I'll probably have enough hot water just from solar and from cruising in summer.

 

Does anyone know the name of the valves I'm looking for? Are they just called "Manual radiator valves"? They have inlet sizes of 15mm and come out the sides, except the towel rail whose 15mm inlet valves are at the bottom.

Edited April 6, 2021 by jetzi

[Chewbacka]

16 minutes ago, jetzi said:

Oh dear, what can be done about this? Use copper?

 

 

  

This was extremely helpful to read, thank you!

 

My calorifier coil does not have balance valves, and in fact I think this might have been causing the original problem I had with the Eber - with my radiators only getting somewhat warm,

 

I think what I need to do therefore is to fit manual valves to all 4 radiators AND the calorifier circuit which I can use for balancing, and once balanced, ensure that I never switch off the towel rail. The other radiators I can, if I choose to, use the balance valve to turn off in the Summer months to heat only hot water (and towels). However my expectation is that I'll probably have enough hot water just from solar and from cruising in summer.

 

Does anyone know the name of the valves I'm looking for? Are they just called "Manual radiator valves"? They have inlet sizes of 15mm and come out the sides, except the towel rail whose 15mm inlet valves are at the bottom.

Something like this?

https://www.toolstation.com/angled-radiator-valve-cp/p15063

As you will be putting glycol in your system (which is excellent at weeping from the seals) if buying valves which have a tiny amount of ptfe tape on, it’s best you take it of and put on some decent stuff or use a demountable thread seal suitable for hot water or it will weep.  Like wise if using plastic pipe be very careful to not scratch the pipe at the joins.

Edited April 6, 2021 by Chewbacka

[Tracy D'arth]

You have to make provision for expansion. If you have a long straight run, there has to be space at the ends for it to move when it expands.

 

The towel rail will need in line straight valves, radiators angled valves. Buy decent ones like Pegler Yorkshire rather than the cheap Italian junk that leak from the glands especially with antifreeze..

[jetzi]

3 hours ago, Chewbacka said:

Something like this?

https://www.toolstation.com/angled-radiator-valve-cp/p15063

As you will be putting glycol in your system (which is excellent at weeping from the seals) if buying valves which have a tiny amount of ptfe tape on, it’s best you take it of and put on some decent stuff or use a demountable thread seal suitable for hot water or it will weep.  Like wise if using plastic pipe be very careful to not scratch the pipe at the joins.

Great, thank you!

 

I presume each radiator just needs one, and can use a plain elbow on the other side?

 

Lastly regarding the glycol, should I be using the same mixture as I do for my engine/skintanks?

[Alan de Enfield]

15 minutes ago, jetzi said:

Lastly regarding the glycol, should I be using the same mixture as I do for my engine/skintanks?

 

Glycol alone is not good enough - you need an antifreeze with rust inhibitors otherwise your radiators will very quickly become perforated and leak.

[jetzi]

I have been using Prestone antifreeze/coolant (20 litre ready mixed for 55 gbp: https://www.ebay.co.uk/itm/Prestone-20-litre-Ready-to-Use-Coolant-Guaranteed-for-All-Cars/393232181982)

 

I'm sure it's not the cheapest but it has the advantage of being mixable with any other types of antifreeze. And being that I haven't changed the coolant since I bought the boat, I don't know what kind is in there at the moment. I have been using concentrate mixed with tap water but I would like to replace it with a proper mix of antifreeze and distilled water (or ready mixed like the link).

 

Since I have to drain the cooling system I may as well take the opportunity to replace the coolant. Simplest would be if I can use the same mix for my eber/rad/cauli circuit as my engine/skintank/cauli circuit.

 

I don't mind spending more to get the best.

[Tracy D'arth]

You would be advised to fit a radiator valve and a lockshield valve to every radiator then you can balance the heat output using the lockshield valves and be able to remove a radiator without draining it all down.

Talking of which, don't forget drains at the lowest point for when you have to empty and flush out and refill.

[cuthound]

53 minutes ago, jetzi said:

Great, thank you!

 

I presume each radiator just needs one, and can use a plain elbow on the other side?

 

Lastly regarding the glycol, should I be using the same mixture as I do for my engine/skintanks?

 

Depends on the mix. I use 50% antifreeze to water in my engine, however the rads didn't get hot when I used that mix in them.

 

I had to reduce it to 33% antifreeze to get the rads hot.

[Tracy D'arth]

8 minutes ago, cuthound said:

 

Depends on the mix. I use 50% antifreeze to water in my engine, however the rads didn't get hot when I used that mix in them.

 

I had to reduce it to 33% antifreeze to get the rads hot.

High concentrations of antifreeze tend to fail to diffuse into  the water and settle as a stratified layer in the low points of the system. For this reason the water and antifreeze must always be mixed before use.

[cuthound]

9 minutes ago, Tracy D'arth said:

High concentrations of antifreeze tend to fail to diffuse into  the water and settle as a stratified layer in the low points of the system. For this reason the water and antifreeze must always be mixed before use.

 

Indeed, and it was thoroughly mixed before the system was filled.

 

I also used a hot air gun on the rads to get it to circulate, but when I turned the heating off after a few hours and let it cool down, the radiators refused to heat up again without help.

[jetzi]

53 minutes ago, Tracy D'arth said:

You would be advised to fit a radiator valve and a lockshield valve to every radiator then you can balance the heat output using the lockshield valves and be able to remove a radiator without draining it all down.

Thanks, I'll do that. It looks like the valves come with both a "tap" attachment and a "lockshield" attachment so I can use the same one on each side.

 

So that's 6x https://www.toolstation.com/angled-radiator-valve-cp/p15063

and 2x https://www.toolstation.com/inline-radiator-valve-cp/p73348

 

Totalling 25.84 gbp.

 

Seems fair.

 

For the coolant:

• 2x skin tanks, external dimensions 1250x480x60 = 36 litres max each (if completely hollow and no skin thickness) = 72 litres
• 3x double panel rads 1000x600, assuming 10mm thickness uniformly (generous) = 0.6 litres each = 1.8 litres
• 1x Towel rail is 750*600, assuming 10mm thickness uniformly  = 0.45 litres
• Engine coolant capacity - 7.4 litres
• 30m of 22mm pipe run for the central heating system = 9.45 litres
• 4m of 2" pipe for the engine cooling system = 7.8 litres

Grand total of about 100 litres of coolant needed...

 

So, 5x of those 20l prestone ready mix coolants which would be 275 quid ?

 

I think I need to find a more affordable coolant...