How to drain Calorifier

[Onewheeler]

19 minutes ago, David Mack said:

That won't work if there is a non return valve fitted to the calorifier inlet.

True! I had one on one boat and removed it as it made winterising harder.

[Katie]

6 hours ago, Briss said:

This may help... setting up an accumulator: https://www.thefitoutpontoon.co.uk/plumbing/accumulator/

Thanks. This says to set the accumulator at the CUT IN pressure of the pump is that correct? Not the cut out pressure? I’ve adjusted it to the cut in pressure and it’s still running for a long time after tap is turned on. 

1 hour ago, MtB said:

 

Next time?

 

I'm still curious about why this one needed to be changed in the first place! 

 Tank was leaking 

[blackrose]

On 02/01/2022 at 09:45, Katie said:

Thanks just tried shutting off valve from water tank and disconnecting the inlet to the water pump. Opened all taps and didn’t work. Just a trickle of water and then basically stopped. 
 

at this point I think it’s just easier to drain the whole system including water tank. 
 

 

 

Seem to be a lot of complicated suggestions here but this is my advice:

 

It's the vacuum inside the calorifier which prevents the water from coming out. So if you twist the PRV at the top of the calorifier (assuming vertical) you should find that water comes out of your drain pipe or any other pipe that you've disconnected.

 

You can use the PRV to control how much water comes out at any one time. I just filled a washing up bowl about 8 times until it was empty. 

[Katie]

10 minutes ago, blackrose said:

 

Seem to be a lot of complicated suggestions here but this is my advice:

 

It's the vacuum inside the calorifier which prevents the water from coming out. So if you twist the PRV at the top of the calorifier (assuming vertical) you should find that water comes out of your drain pipe or any other pipe that you've disconnected.

 

You can use the PRV to control how much water comes out at any one time. I just filled a washing up bowl about 8 times until it was empty. 

Thanks probably would of worked better but we’ve done it now just removed it while water was in the tank and drained it out off the boat 

[Iain_S]

2 hours ago, Katie said:

Thanks. This says to set the accumulator at the CUT IN pressure of the pump is that correct? Not the cut out pressure? I’ve adjusted it to the cut in pressure and it’s still running for a long time after tap is turned on. 

 Tank was leaking 

Cut in pressure is correct. If it's set to cut out pressure, the accumulator won't do anything. Pump running on after tap off is a sign that accumulator (or equivalent with air in system) is working. There should also be a delay in pump starting when a tap is opened.

[Briss]

Have you got all the air out of the pipes (e.g. the shower) so the pump isn't working to pressurise that air as well as the accumulator?

[Tracy D'arth]

To set accumulator pressure to pump cut in pressure.

Pump air into accumulator valve to over the pump cut out pressure, say 50psi if you don't know the pressure.

Run pump with a tap open, close tap and wait for pump to stop.

Very slowly let air out of accumulator by pressing valve pin until the pump just cuts back in.

Job done.

[Katie]

Thanks all just wanted to double check. The accumulator was at the cut OUT pressure when I first checked it and expansion had no pressure at all!  
 

Now have the accumulator set at cut in pressure and the expansion set at just above the cut out. I will keep rechecking the pressures over next few days. 
 

Pump still running for seemingly much longer time than needed but I suspect still some air in the system. did get a fair bit of air out when I ran the tap after these adjustments so I’ll see how it goes over next few days or so. 
 

also I am comparing it to the previous set up which was clearly wrong as my pump would go off as soon as any tap turned on which I now understand is because the accumulator must not of been holding hardly any water if it’s pressure was too high! 
 

[blackrose]

Accumulator tanks should be set at approx 3 or 4 psi BELOW water pump CUT-IN pressure.

Hot water expansion vessels should be set at or slightly above water pump CUT-OUT pressure.

Both set with the water pump switched off and a couple of taps open to release pressure in the system.

 

This needs to be pinned somewhere please.

[Tracy D'arth]

1 hour ago, blackrose said:

Accumulator tanks should be set at approx 3 or 4 psi BELOW water pump CUT-IN pressure.

Hot water expansion vessels should be set at or slightly above water pump CUT-OUT pressure.

Both set with the water pump switched off and a couple of taps open to release pressure in the system.

 

This needs to be pinned somewhere please.

Can someone tell me a method of checking the pressure in a bladdered vessel without any air escaping when connecting or attaching a pressure gauge or air pump?

Due to the small volume of most boat expansion vessels or accumulators and low setting pressures, the lost pressure when checking can make a significant difference.

I suppose a permanently attached gauge with a separate valve  for charging would be better but I have never seen such a set up.

[blackrose]

4 minutes ago, Tracy D'arth said:

Can someone tell me a method of checking the pressure in a bladdered vessel without any air escaping when connecting or attaching a pressure gauge or air pump?

Due to the small volume of most boat expansion vessels or accumulators and low setting pressures, the lost pressure when checking can make a significant difference.

I suppose a permanently attached gauge with a separate valve  for charging would be better but I have never seen such a set up.

 

I just use a tyre pressure gauge. If you get it square onto the valve when you push it in very little air (or nitrogen) should escape.

[Katie]

On 06/01/2022 at 10:18, blackrose said:

Accumulator tanks should be set at approx 3 or 4 psi BELOW water pump CUT-IN pressure.

Hot water expansion vessels should be set at or slightly above water pump CUT-OUT pressure.

Both set with the water pump switched off and a couple of taps open to release pressure in the system.

 

This needs to be pinned somewhere please.

Thanks. Have done this now and my pump is definitely not cycling as long after taps have been on and I get the delay of it kicking in as water from accumulator is used first. 
 

odd thing now is the water pressure in my bathroom (closest to water pump) is quite high and the kitchen (furthest away) is really low on both hot and cold (almost just a trickle). Not sure why or how to even this out? It was fine when we first fitted the new calorifier seems to have dropped after I’ve played about with the accumulator and expansion tank pressures. But I wouldn’t of thought this should affect pressure of flow from the taps? Perhaps a blockage? 

[Ex Brummie]

Is your pressure low with the pump running, or just until it cuts in?

[Katie]

6 minutes ago, Ex Brummie said:

Is your pressure low with the pump running, or just until it cuts in?

Low with pump running too but only at the kitchen tap on both hot and cold 

 

bathroom is fine maybe a bit high 

[MtB]

On 06/01/2022 at 11:49, Tracy D'arth said:

Can someone tell me a method of checking the pressure in a bladdered vessel without any air escaping when connecting or attaching a pressure gauge or air pump?

 

No. I've never managed to discover or think of a way.

 

HST the volume of air escaping when connecting or disconnecting a gauge is tiny provided to press the gauge on cleanly and squarely. Tiny compared to the volume in even tiny expansion vessels, but I agree it make a big difference on the really small shock arrestor vessels of 50 to 100cc volume on domestic systems and thermal stores. 

[WillCful]

On 06/01/2022 at 11:49, Tracy D'arth said:

Can someone tell me a method of checking the pressure in a bladdered vessel without any air escaping when connecting or attaching a pressure gauge or air pump?

Due to the small volume of most boat expansion vessels or accumulators and low setting pressures, the lost pressure when checking can make a significant difference.

I suppose a permanently attached gauge with a separate valve  for charging would be better but I have never seen such a set up.

Some of the more expensive bike hand pumps have a sort of two part shrader nozzle that screws on to the valve and then screws down again to press on the pin and open the valve. To release you then unscrew to release the valve pin first with no loss of air and then unscrew again to remove the hand pump. 
 

I think I did a crap job of explaining that but if you see one it makes sense. They’re known as ‘shock pumps’ in the mtb community and usually have pressure gauges. However they’re designed for high pressure bike suspension (200+ psi) so the gauges are next to useless for low pressure accumulators. 
 

I think you can also get digital pressure readers (again, can be found on bike websites) that have this same no-loss release mechanism, and are very accurate. Some also have a button so you can release pressure with the gauge in place down to your desired setting and then remove the gauge without altering the set pressure, very handy. 

[Katie]

1 hour ago, WillCful said:

Some of the more expensive bike hand pumps have a sort of two part shrader nozzle that screws on to the valve and then screws down again to press on the pin and open the valve. To release you then unscrew to release the valve pin first with no loss of air and then unscrew again to remove the hand pump. 
 

I think I did a crap job of explaining that but if you see one it makes sense. They’re known as ‘shock pumps’ in the mtb community and usually have pressure gauges. However they’re designed for high pressure bike suspension (200+ psi) so the gauges are next to useless for low pressure accumulators. 
 

I think you can also get digital pressure readers (again, can be found on bike websites) that have this same no-loss release mechanism, and are very accurate. Some also have a button so you can release pressure with the gauge in place down to your desired setting and then remove the gauge without altering the set pressure, very handy. 

Yea I made mistake of buying shock mob pump and gauge set too high to get accurate reading. 
 

i bought a cheap digital gauge form go outdoors for about £8. Lost no more than 0.5 PSI through repeat testing so I just accounted for that when using bike pump to adjust pressure. 
 

 

in other news… sorted my pressure problem in kitchen tap! Was just a load of crap blocking the aerator on the end of the tap. Easy fix. Glad I checked that before anything else!