Water Pump and Instant Gas Heater

[StarUKKiwi]

Hi, I am not a plumber so forgive me. We have an instant gas water heater, last night it ignited on its own and the water pump kept running. We can hear water running in the pipes, but can't find any leaks, thoughts and possible solutions welcome

[MtB]

On 23/07/2017 at 11:09, StarUKKiwi said:

Hi, I am not a plumber so forgive me. We have an instant gas water heater, last night it ignited on its own and the water pump kept running. We can hear water running in the pipes, but can't find any leaks, thoughts and possible solutions welcome

 

Sounds to me as though you have a big leak. On a hot pipe somewhere. You really need to find it urgently.

Check your bilges. Is there a bilge pump operating too?

Is your water tank level falling unexpectedly quickly too?

[Chewbacka]

To keep the pump and gas heater running continuously I would expect a big leak,  if you don't find it soon you will get wet feet.....

I would turn off the gas heater & pump, and isolate the water supply from the tank to the pump and then start following the pipes after the water heater as a leak before the water heater should not turn the water heater on.

[StarUKKiwi]

We turned both off as soon as it happened, we have an automatic  bilge pump 

[Tony Brooks]

That pump may only be for the engine bilge unless its an older boat with an all in one bilge. Check there are holes in the rear bulkhead to allow water to drain back arround the engine area. If not locate or cut a trap in the floor just in front of the rear bulkhead in the accommodation floor. It is often in a cupboard or under the rear steps.

[StarUKKiwi]

Yes we an all in one bilge pump also a back trap, problem being I can't use my left arm due to my fistula and lifting is out of the question 

[Flyboy]

1 hour ago, StarUKKiwi said:

Hi, I am not a plumber so forgive me. We have an instant gas water heater, last night it ignited on its own and the water pump kept running. We can hear water running in the pipes, but can't find any leaks, thoughts and possible solutions welcome

Check the PRV on the calorifier if you have one. This should discharge through a skin fitting but sometimes they go into the bilge. Locate the PRV and turn the knob which usually clicks, this should clear any lime scale build up which may be holding the valve open.

I think you have a big leak on a hot water pipe.

Edited July 23, 2017 by Flyboy

[bizzard]

I doubt there is a calorifier as it has an Instantaneous gas hot water heater. If it has then it will almost certainly have a Y type hot water change over valve.  If that back trap is in the floor at the rear of the accommodation it needs to be opened to check for water in the bilge PRONTO!!!

[bizzard]

16 minutes ago, Flyboy said:

Check the PRV on the calorifier if you have one. This should discharge through a skin fitting but sometimes they go into the bilge. Locate the PRV and turn the knob which usually clicks, this should clear any lime scale build up which may be holding the valve open.

I think you have a big leak on a hot water pipe.

We have a boat here called Phoebe.

[StarUKKiwi]

1 hour ago, Flyboy said:

Check the PRV on the calorifier if you have one. This should discharge through a skin fitting but sometimes they go into the bilge. Locate the PRV and turn the knob which usually clicks, this should clear any lime scale build up which may be holding the valve open.

I think you have a big leak on a hot water pipe.

We dont have a califorifier, just instant hot water tank

1 hour ago, bizzard said:

I doubt there is a calorifier as it has an Instantaneous gas hot water heater. If it has then it will almost certainly have a Y type hot water change over valve.  If that back trap is in the floor at the rear of the accommodation it needs to be opened to check for water in the bilge PRONTO!!!

Will do, i checked it only last week, but i will check it when OH get home (i can't lift the stairs up on my own). The leak must be between the heater and one of the two hot water taps, either in the galley or the bathroom. Do i then need to take the fridge and oven out as the pipes are behind them? 

Edited July 23, 2017 by StarUKKiwi
To add what i missed and autotype fail

[StarUKKiwi]

@bizzard what is a " Y type hot water change over valve"?  Thanks in advance 

[MtB]

On 23/07/2017 at 13:34, StarUKKiwi said:

@bizzard what is a " Y type hot water change over valve"?  Thanks in advance 

 

Its special format valve used to switch between a calorifier and a Morco. You won't have one as you don't have a calorifier. 

 

Rather that switching the flow ON and OFF, it switches the flow between output A and output B.

[alan_fincher]

If water is running freely somewhere in enough volume to cause not only the pump to start, but the Morco to fire up as well, then it is a significant flow.  Instantaneous heater tend not to start up unless the flow is quite fast.

If your boat uses push fit plumbing like Hp2) or Speedfit, (the most common arrangement), I would suspect that there is a good chance that a joint has come right apart, and water is puring out at least as fast as if a tap were flly open.

No idea why it would have done it now though - joints getting frozen up can force those fittings apart, or split the screwed rings on them, but clearly we have had no recent frosts.

[StarUKKiwi]

1 minute ago, alan_fincher said:

If water is running freely somewhere in enough volume to cause not only the pump to start, but the Morco to fire up as well, then it is a significant flow.  Instantaneous heater tend not to start up unless the flow is quite fast.

If your boat uses push fit plumbing like Hp2) or Speedfit, (the most common arrangement), I would suspect that there is a good chance that a joint has come right apart, and water is puring out at least as fast as if a tap were flly open.

No idea why it would have done it now though - joints getting frozen up can force those fittings apart, or split the screwed rings on them, but clearly we have had no recent frosts.

No, it was at 7.30pm last night, i was glad it did it when i was home and not just after i had gone for dialysis as i am gone for about 6 hours

[alan_fincher]

Just now, StarUKKiwi said:

No, it was at 7.30pm last night, i was glad it did it when i was home and not just after i had gone for dialysis as i am gone for about 6 hours

I can only guess that a fitting was already part failed/cracked/separated, and picked then to finally die completely.

I'll be surprised if it doesn't prove to be that, assuming you don't have water streaming down from the heater itself - something I doubt you could miss!

Should be a cheap fix, provided the joint involved is not hidden.  (Our latest boat has many in places they can't be accessed, including under floors, which is far from ideal if things like this happen).

Try looking in cupboards under sinks and wash basin(s) and around any shower plumbing that you can expose.  If it is a joint that has got frozen and part failed during a previous winter, it is more likely to be a high up one than a low down one.  Because the canal never goes sub zero far below the surface, and low down plumbing inside well below water line tends not to freeze up as a result.

[MtB]

I agree with Alan, it is almost certainly a joint come apart. 

There is no immediate urgency to find/fix it though given you've turned the water pump OFF. The only urgency is to get it fixed so you can have a water supply again!

You mentioned being able to hear water flowing when the pump is ON. I'd start looking for pipes to check for failed joints right where you heard water flowing.

[DHutch]

1 hour ago, Mike the Boilerman said:

I agree with Alan, it is almost certainly a joint come apart. 

There is no immediate urgency to find/fix it though given you've turned the water pump OFF. The only urgency is to get it fixed so you can have a water supply again!

You mentioned being able to hear water flowing when the pump is ON. I'd start looking for pipes to check for failed joints right where you heard water flowing.

Indeed.

In the mid position, will the change over valve isolate both feeds, allowing you to use the cold side as normal while a fix is effected?

We have two on-off valves for each hot water system rather than a change over 'y-valve' so it's easy to do.

Daniel

[MtB]

Dan, there is no changover valve, and no calorifier.

This unnecessary confusion and complication has been caused by flyboy not reading the thread, followed by you so it seems!

[bizzard]

In my opinion it is very very important that the water pump is switched off when the boat is left unattended, otherwise on returning to the boat you could be faced with it full of water. A pipe or joint could fail on anyones boat and the pump won't stop pumping all the water from your tank unless the batteries go flat or the pump fails.

[DHutch]

26 minutes ago, Mike the Boilerman said:

Dan, there is no changover valve, and no calorifier.

Ah right, sorry. Isolator on the inlet of the hot water heater? Might be a good time to fit one!

27 minutes ago, bizzard said:

In my opinion it is very very important that the water pump is switched off when the boat is left unattended, otherwise on returning to the boat you could be faced with it full of water. A pipe or joint could fail on anyones boat and the pump won't stop pumping all the water from your tank unless the batteries go flat or the pump fails.

Yes, we always* turn off the main isolator on leaving for more than an evening. Which in part isolates the pump.

[DHutch]

*I actually forgot once, a few weeks ago, came back after three weeks to batteries at about 21volts. Oops. Mainly I think due to parasitic load from the multiple USB outlets fitted last year. Still once in 10 or more years, maybe 100 trips, isn't too bad.

 

Daniel

[StarUKKiwi]

22 hours ago, bizzard said:

In my opinion it is very very important that the water pump is switched off when the boat is left unattended, otherwise on returning to the boat you could be faced with it full of water. A pipe or joint could fail on anyones boat and the pump won't stop pumping all the water from your tank unless the batteries go flat or the pump fails.

Yes I think it is advisable 

[StarUKKiwi]

Thanks for all the advice, we found it today, a blown joint for hot water tap into the bathroom. All fixed and working. It had to wait until I had been to the unit today. But we know what it was, double checked all the other joints and they were fine. So I don't know what caused it. Checked the bilge hatch as well and there wasn't too much water, but I think that was because we turned the water off straight away 

[ditchcrawler]

12 minutes ago, StarUKKiwi said:

Thanks for all the advice, we found it today, a blown joint for hot water tap into the bathroom. All fixed and working. It had to wait until I had been to the unit today. But we know what it was, double checked all the other joints and they were fine. So I don't know what caused it. Checked the bilge hatch as well and there wasn't too much water, but I think that was because we turned the water off straight away 

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