Water pump and/or accumulator problems...

[Jaywire]

Hello! New to narrowboat life, bought a 20 year old boat a few months ago and having some problems with the water system that I can't get my head around.

 

Everything seemed to be working fine at first but very soon I noticed that the pump was switching on/off more frequently and the pump was switching on for very short periods (a second or two) two or three times a night.

 

I checked for leaks, no evidence of such and then checked accumulator pressure and it was close to 0, so pumped to 20psi as my pumps cut off pressure is 25psi.

 

It worked better for a short while but soon started switching on/off more frequently and switch on at night for no reason. So I assumed that the accumulator was loosing pressure (air comes out of valve, not water).

 

Checking the accumulator pressure again, it was close to 0psi again (this was about 10 days after setting it to 20psi).

 

I followed the advice on this thread  - https://www.canalworld.net/forums/index.php?/topic/55716-accumulator-tank-pressure/ - to find the pumps actual cut in pressure:

 

 1. Deflate and lightly (5-10 psi) re-pressurise the accumulator

 2. Pump on, taps off until the pump stops

 3. Tap on slowly until the pump starts

 4. Stop pump and turn taps off as quick as you can. (these last two steps may need a bit of practice)

 5. Read the pressure in the accumulator

 6. Taps on till the water stops

 7. Pressurise the accumulator to the pressure read above.

 8. Taps off, pump on. Wait till it stops.

 

But my pump started immediatly as soon as I turned the tap on in step 3, so it appeared to me that my pumps cut-in and cut-out pressure were almost the same, which I'm guessing isn't right.

 

Also, after following those steps my water came out dirty for a while, with what looked like rust in it, which is a first and our water tank is stainless.

 

The anoying thing is that the pump seems to be inconsistant, sometimes it turns on and off with opening and closing a tap. Othertimes the pump runs for 'a while' after closing a tap to build up some pressure in the system.

 

My hunch is my accumulator isn't working as it should, loosing pressure and potentially rusty inside, so step 1 would be to replace that and then I can test my pump with a new accumulator installed to troubleshoot any problems with the pump itself.

 

It feels to me as if the pumps cut in / out pressures seem to vary, but I've never had a pump behave like that before, is that something that can happen?

 

Just thought I'd post on here to see if anyone's got anything to add. Sorry about the long first post!

[Tony Brooks]

Sounds like a leaking accumulator to me.

 

Check any PRV on the calorifier is not weeping.

[Tracy D'arth]

Pump coming on at night is a leak somewhere that you have yet to find (PRV?)  or valve in pump leaking back. There is no other reason.

You need  a new accumulator.

 

To set the pressure without a gauge, pump it up to over the pump pressure with pump off and a tap open.

Switch pump on and let it run, then turn tap off, let it run till it stops.

Very slowly dump air from accumulator until pump just cuts back in.

Done.

[jonathanA]

18 minutes ago, Tracy D'arth said:

To set the pressure without a gauge, pump it up to over the pump pressure with pump off

sorry Tracy - am I reading that wrong how can you "pump the accumulator up to over the pump pressure" without a gauge...  

[Tracy D'arth]

8 minutes ago, jonathanA said:

sorry Tracy - am I reading that wrong how can you "pump the accumulator up to over the pump pressure" without a gauge...  

Just pump it till the bike pump is getting harder to push. It will then likely be something like 40 to 50 psi. As long as it is higher than the pump cut off pressure it does not need to be accurate.

[ditchcrawler]

40 minutes ago, Tracy D'arth said:

Pump coming on at night is a leak somewhere that you have yet to find (PRV?)  or valve in pump leaking back. There is no other reason.

You need  a new accumulator. 

 

Don't miss this bit

[Tony Brooks]

7 minutes ago, ditchcrawler said:

Don't miss this bit

 

I am sure the OP said that there was no pressure in the accumulator so he pumped it up, and later he again found no pressure. Add that to rusty water, and you get the impression the diaphragm has split.

[Iain_S]

Pump coming on for a second or two at night may be due to calorifier cooling, especially if accumulator is U/S.

[Jaywire]

Thanks for all the replies.

 

Checked the PRV valve and it's dry as a bone. Double checked for leaks and again can't spot anything.

 

I'll replace the accumulator as I'm now convinced it's knackered.

 

If problems persist or I come across anything interesting I'll post again.

 

Cheers!

 

 

[Tracy D'arth]

If you cannot find any leak or loss of water elsewhere, at night turn off the tap between the tank and the pump, i.e. the main stop tap. If then the pump does not come on as it did before, it must be leak back through the pump valves causing the pressure to drop..

[ditchcrawler]

With no working accumulator then even temperature variations could cause it to blip

[jeanb]

We experienced a similar problem which required a new accumulation as the bladder had split. What we would like to know please is how do we know when a prv is knackered? i.e. (i) does it leak all the time or (ii) not leak at all and the calorifier goes boom. Thanks for any replies.

(With apologies for piggybacking on another post).

[Tony Brooks]

26 minutes ago, jeanb said:

We experienced a similar problem which required a new accumulation as the bladder had split. What we would like to know please is how do we know when a prv is knackered? i.e. (i) does it leak all the time or (ii) not leak at all and the calorifier goes boom. Thanks for any replies.

(With apologies for piggybacking on another post).

 

Usually the PRV weeps all the time and sometimes you can flush limescale off the seat by twisting the knob a few times with the pump turned on.

 

The PRV will scale up unless you also have an expansion vessel or there is no one way valve between the accumulator and PRV.

[Jaywire]

Just fitted the new accumulator, as suspected the old one was shedding rust and the rust had built up and pretty much blocked the T-junction below the accumulator.

 

Gave everything a good clean out, fitted and set the pressure on the new accumulator and everything seems to be working nicely.

 

Thanks!

[Tracy D'arth]

17 minutes ago, Jaywire said:

Just fitted the new accumulator, as suspected the old one was shedding rust and the rust had built up and pretty much blocked the T-junction below the accumulator.

 

Gave everything a good clean out, fitted and set the pressure on the new accumulator and everything seems to be working nicely.

 

Thanks!

Great, thanks for reporting back.

[cutandpolished61]

On 18/08/2023 at 16:56, Tracy D'arth said:

If you cannot find any leak or loss of water elsewhere, at night turn off the tap between the tank and the pump, i.e. the main stop tap. If then the pump does not come on as it did before, it must be leak back through the pump valves causing the pressure to drop..

Have the same problem with the water pump coming on every 40 minutes for 1 second. Closed the main stop tap but still the pump is coming on by making a sound like a noisy fan running continuously. 

[Tony Brooks]

56 minutes ago, cutandpolished61 said:

Have the same problem with the water pump coming on every 40 minutes for 1 second. Closed the main stop tap but still the pump is coming on by making a sound like a noisy fan running continuously. 

The answers to your problem are all within this topic. What pressure, if any, do you have in your accumulator - assuming that you have one.

[Tracy D'arth]

1 hour ago, cutandpolished61 said:

Have the same problem with the water pump coming on every 40 minutes for 1 second. Closed the main stop tap but still the pump is coming on by making a sound like a noisy fan running continuously. 

Sounds like a leak that you have yet to find. Check all the pipes from the pump to all the outlets.

[cutandpolished61]

Checked for any leaks already. Accumulator installed last year but pressure was never checked. Pump comes on as soon as I open the tap. When I open the tap fully then the pump stops for a second or two and then comes on again. It was like that from day one when installed by a plumber. During the summer the pump came on 5-6 times a day for a second with all taps closed. Now this is happening more frequently every 40 minutes or so. I checked the suppliers website which states that  accumulators will be shipped without pressure in the tank but only to overseas buyers. Now I'm wondering that I received one of these 

[Alan de Enfield]

4 minutes ago, cutandpolished61 said:

Now I'm wondering that I received one of these 

 

Why don't you just check ?

 

Rather than speculate as to the potential fault, and ask others to do the same, it is a fairly simple fault finding process.

 

[cutandpolished61]

I know, need to get a gauge first. Don't think that I can just use a pump without checking the pressure. 

[Tracy D'arth]

Zero pressure in the accumulator will not cause the pump to start up occasionally with all the taps closed. Either you have a leak which you have yet to find or the pump is passing back to the tank. Turn the tap between the tank and the pump off, if it stops coming on then its the pump passing. If it still does it you have a leak!

1 minute ago, cutandpolished61 said:

I know, need to get a gauge first. Don't think that I can just use a pump without checking the pressure. 

No gauge needed, I can tell you how to do it without but you need to stop this cycling first, the accumulator is not the problem even if it needs pumping up.

[ditchcrawler]

1 hour ago, cutandpolished61 said:

  Pump comes on as soon as I open the tap.  

That alone tells me the accumulator is not working and its almost certain it is at too high a pressure 

[cutandpolished61]

Please tell me how to re pressurise correctly without a gauge as I'm worried that I might damage the bladder 

[ditchcrawler]

30 minutes ago, cutandpolished61 said:

Please tell me how to re pressurise correctly without a gauge as I'm worried that I might damage the bladder 

You cant damage the bladder