No hot water

[Markinaboat]

Firstly, a very happy new year to all .

So, collected new (used) boat 10 days ago and en route home. New pump and taps fitted as they didn't winterise and they all blew. All worked fine for a few  days. We left the boat for two days over Xmas so I isolated the tank supply and left all taps open, pump switched off. Then, on our return, water and pump on and vlisedctsps which were all flowing. However, when using hot water from bathroom tap and shower, pump cycling on and off (but not in galley which must be a higher flow tap). But we had hot water and with a cold tap slightly open, could shower without cycling. Back today for leg three from MK to Harefield and after three hours of heating being on , still cycling on hot taps  but no hot water. Drained off some water from pressure relief on calorifier and not hot, maybe ever so slightly tepid. The rads in the boat are nice and hot and the heating circuit header tank level looks normal. 

Any ideas greatly appreciated as the prospect of 5 days cruising in all weathers without a shower is daunting. 

 

[MtB]

9 hours ago, Markinaboat said:

Drained off some water from pressure relief on calorifier and not hot, maybe ever so slightly tepid

 

Well this has to be the immediate problem, and it’s probably nothing to do with the problem you describe with new pump and taps.

How are the calorifier and the (Hot) radiators heated? Just the engine or is there a webasto or something?

Whichever though, there is no water from the heat source curculating through the heating coil inside the calorifier. The task now is to find out why, hence my question.

Happy new year to you, too! 

[Sea Dog]

Hmm, more than one issue I suspect  particularly as a lot of work has been done on the fresh water system. Your central heating system is separate. Mtb has just asked what sort of system you have as I type, which was also my first question!

My main point:  You probably also have hot water from your engine heating your calorifier, so all may not be lost.

Something to check:  If your central heating is diesel like, say, a Webasto, first check for air which might cause a lock. Bleed the rads too to make sure your system is air free, otherwise you might just pump some more air to wherever it might cause a problem. 

Next, there's a balance valve which throttles the flow to your coil in the tank. Too far open and the hot water returns to the boiler too quickly and causes cycling of the heater; not open enough and you'll get hot rads but not enough heat going in to make sufficient hot water. No reason for this to have been disturbed, but who knows whether it was ever right? Check it's not been closed - if it's a valve with a screwdriver slot, 90 degrees across the line of flow is fully shut. If it hasn't been closed, beware of fiddling here if you're not sure what you're doing.

[MtB]

22 minutes ago, Sea Dog said:

My main point:  You probably also have hot water from your engine heating your calorifier, so all may not be lost.

 

Yes if there is a twin coil calorifier the engine will have been heating the water during the trip, masking the webasto fault which has perhaps been present all along. 

[13-10]

3 hours ago, Sea Dog said:

Too far open and the hot water returns to the boiler too quickly and causes cycling of the heater;

Sorry if I'm asking a stupid question but whats 'cycling' in this context

[Chewbacka]

cycling = turning on and off and on and off because the system is not 'losing' enough heat and the water goes back to the boiler too hot so the boiler turns off for a bit.  Frequent stop/start leads to lots of crap being built up. 

[13-10]

Thanks for that

[Richard10002]

3 hours ago, Mike the Boilerman said:

 

Yes if there is a twin coil calorifier the engine will have been heating the water during the trip, masking the webasto fault which has perhaps been present all along. 

In the short term, if the engine is heating the water in the calorifier, there is no need to be without hot water.

Given that they are on a trip, my assumption is that there is no hot water in the calorifier, from either the engine heating it, or the central heating system. I may be wrong, but this would be identified by running the engine for an hour, followed by checking the hot water situation again.

Again, in the short term, 5 days without a shower or bath shouldn’t be the end of the world, but I would find it irritating to have to boil a kettle for every wash, whether hands, face, or pots

[Markinaboat]

UPDATE: Thanks for all the replies and apologies for not updating earlier but not long moored up. Firstly, I am au fait with boat systems as many years living aboard. Firstly the hot water issue. I think this was a red herring as when we collected the boat from  Hanbury, we were on shore power and I no doubt used the immersion. Then 8 days cruising over two trips we of course had hot water from the engine circuit. When we arrived back at the boat last night, I put the Eberspacher on and we didn't get hot after 4hrs (rads piping hot). The regulation valve to the calorifier was partially open so I opened it further but still no good. I've had webasto's previously and no issues so maybe the Eber thingy takes a significant amount of time from cold, especially with the weather we're having. So I'm not too concerened about this now. 

The original issue of the pump cycling when running hot water (and cold from the bathroom tap) is however a mystery, especially as this was not happening for  the first 5 days. To recap, the broker had installed a new parmax 2.9 as well as bathroom, galley and shower mixer taps as they had burst whilst on hard standing at a marina when we had the -13c night. Other than a few initial leaks where I had to tighten up joints, all was fine. The only thing I did at the end of the initial 5 day trip was to isolate the main water tank, opened all taps and of course turned the pump off. The water pressure in the system is obviously such that it's stopping the pump every 1 or 2 seconds. How on earth could it have worked then change just like that?

Aching bones and muscles from the cold with a chronic back and basically minging in the presence of the other 'alf requires me to have a nice hot shower at the end of the day as I have had with all of my boats thank you very much! :-)

ps. The pump gives a momentary purr maybe once or twice during the evening but I've heard this could be due to the hot water cooling in the calorifier with a resultant drop in pressure. 

Edited January 1, 2018 by Markinaboat

[WotEver]

8 hours ago, Markinaboat said:

The original issue of the pump cycling when running hot water (and cold from the bathroom tap) is however a mystery, especially as this was not happening for  the first 5 days.

Have you checked the pressure in the accumulator?

It could also simply be that the pressure switch in the new pump has ‘settled down’ and needs slight adjustment to raise the cut out point. 

[Tony Brooks]

Did the pipes running from the central heating into the calorifier get hot? The top one should have got as hot as the rads and the bottom one probably a bit off cold until the calorifier contents warmed up a bit. If not there is no circulation through the calorifier coil so it probably has an airlock in it.

I think the 2.9 probably refers to the pump pressure, not the volume of then output. You can get pumps with different outputs so my guess is the new one has a larger output than the old one. Even if they are identical the old one may well have one or more faulty pumping chambers reducing its output.

[WotEver]

11 minutes ago, Tony Brooks said:

I think the 2.9 probably refers to the pump pressure, not the volume of then output. You can get pumps with different outputs so my guess is the new one has a larger output than the old one. Even if they are identical the old one may well have one or more faulty pumping chambers reducing its output.

But he states that it didn’t cycle for 5 days, then did. That suggests to me that the cut-out pressure has dropped, would you agree?

[Tony Brooks]

4 minutes ago, WotEver said:

But he states that it didn’t cycle for 5 days, then did. That suggests to me that the cut-out pressure has dropped, would you agree?

Could well be.

[Bricksh]

If everything was OK before you shut the pump down and opened the taps, then I would suspect air in the system. When we used to leave the boat we used to do the same. To then recommission, switch the pump on and close the taps, shower, one by one as they stop spitting water out. You may need to repeat this to get all the air out. Over time you will identify which outlets tend to be the worst, for us it was shower and bathroom outlets but depends obviously on the circuit. 

With the eberspacher circuit again could well be air in the circuit. If as you say the radiators are hot, shut off the outlets from the rads to force flow through the calorifier circuit. Keep an eye on the header tank level as when the air comes out this will drop. As soon as you reestablish flow, open the rad valves again.

Jabsco paramax pumps numbers are confusing, they make the 2.9 and others in 2 pressure types, either standard or high pressure, but as it was working OK before can't see that as the problem. If it had started straight after swap it could have indicated the tank pressure relief opening and closing

[WotEver]

32 minutes ago, Bricksh said:

To then recommission, switch the pump on and close the taps, shower, one by one as they stop spitting water out. You may need to repeat this to get all the air out. Over time you will identify which outlets tend to be the worst, for us it was shower and bathroom outlets but depends obviously on the circuit. 

The advice for purging the air on the caravans we’ve owned in the past was always to open the taps which were furthest from the pump first then move towards the nearest. So shower, bathroom, kitchen in that order. Sounds much the same as you advise above. The only difference was that you start with all taps closed then open them one by one in order. 

Same advice for bleeding brakes on a car come to think of it. 

[Edders]

All my boats had a Mikuni fitted and there was always a valve in the outlet piping which allowed the water flow to be varied between the heating circuit and the calorifier circuit. If there is one, could it have been set to full flow to the heating circuit?

Oops, someone has already mentioned this. Sorry.

Tony

Edited January 2, 2018 by Edders

[Bricksh]

Yes much the same. I suppose it comes down to available flow from the pump and if it can supply all the outlets at once or just one at a time. I think the main point being to get rid of the air. Sometimes flow from the tap may indicate no air is trapped, but it can take a while to actually get the air to the outlet dependent on where it is trapped in the system.

I just think its far more likely to be air than the pump pressure switch as the act of shutting off the pump and opening the taps and the hot water then cooling down will pull in air.

Edited January 2, 2018 by Bricksh
Didn't read right

[system 4-50]

With so much frost damage, could there be any other damage affecting the system? 

[Sea Dog]

11 hours ago, Markinaboat said:

I've had webasto's previously and no issues so maybe the Eber thingy takes a significant amount of time from cold, especially with the weather we're having. So I'm not too concerened about this now. 

We're dealing with more than one issue at once here, so I'll not add anything more save to say that an Eberspacher or Webasto of the same output do not perform this significantly differently.  My 4kW Eber has my 57' boat toasty (via radiators) and provides plenty of hot water within the first hour of use on returning to a very cold boat in winter.

[Richard10002]

I have 2 ways of sourcing hot water... either from a Rinnai instant gas water heater, or from a Truma warm air and water heater.

I can’t use both at the same time as this results in two flows of water running against each other, thus reducing the flow, and resulting in a cycling pump. (Being pedantic, the Rinnai always feeds the shower, whichever way the valves are set - 12 litres of hot water from the Truma tank would just about get you soapy before it ran out and became cold  )

i therefore have 2 valves which I open/close as appropriate such that water is only sourced from the Rinnai or the Truma.

Given that the problem started after you had closed and opened some valves, I’m wondering if there is a one sequence of open/closed valves for feeding the calorifier from the engine, and another sequence to feed it from the Eberspacher.

You obviously had it working fine via the engine circuit. Does it still work fine via the engine circuit?

I had to think long and hard about which pipes needed a valve in order to make my system work. I also drew several schematic diagrams in order to understand how things were flowing. When I sell the boat, I am conscious that I will need to explain the workings to a new owner.... otherwise they wouldn’t have a clue.

Can you speak to the previous owner and see if there is a simple answer, which is only obvious once you know it.

[Markinaboat]

Just to reiterate, I have hot water from the engine and no doubt the eberspacher will heat the water up with the regulation valve adjusted so not concerned with that now.

Its the fact that when running hot, the pump pulsates as though pressure is building up due to air or a blockage in the hot water supply, not the heating circuit. But then if an accumulator was fitted (which it isn't for now), then that works on the principle of air being compressed and would not ordinarily reach the pumps cut-off pressure. Ive released some water from the calorifier PRV several times and no air comes out although this is of course on the lower, cooler return connection.

Worked fine for 5 days then stopped. I feel it's a fault with the pump pressure switch which isn't adjustable on these as there's no adjustment screw either outside or under the cover. 

Edited January 3, 2018 by Markinaboat

[Tony Brooks]

Often the adjusting screw is under a label saying something like guarantee void if removed.

[Bricksh]

Have you tried opening each hot water tap for a minute or so to see if any air is expelled?

[Markinaboat]

25 minutes ago, Bricksh said:

Have you tried opening each hot water tap for a minute or so to see if any air is expelled?

Many times and no air.

1 hour ago, Tony Brooks said:

Often the adjusting screw is under a label saying something like guarantee void if removed.

Thanks Tony, I would try this but as they fitted a new pump, I need to get them involved first (rather than void the warranty). We all know that pump settings do change over a period of time, but not after 5 days use and no system changes!? The boat's 4 years old with a stainless tank so can't imagine any debris would have built up and found it's way into the pipework causing a restriction so I keep leaning towards the pump. I've even experimented with the temperature control on the calorifier to see if that makes a difference but it didn't.

 

nb. if there is an adjustment screw, would this change the output pressure or the cut in/cut out pressure? 

Edited January 3, 2018 by Markinaboat

[WotEver]

2 hours ago, Markinaboat said:

nb. if there is an adjustment screw, would this change the output pressure or the cut in/cut out pressure? 

??

Surely adjusting the cut-out pressure IS changing the output pressure? Until it cuts out, all you have is flow, no?

:::waiting for someone to shout NO:::