Troubleshooting

the_lunatic_is_in_my_head

The flow and return from the heat pump to the cylinder has this valve on each pipe, part at the top has a little hole and there is a gargling sound as air is coming out but there is also a small puddle of water on the floor below. 

Very grateful for any advice on what's happening here please. 

Edited to add, I think it's a frost protection valve and I think the water is coming out of the little hole at the top. 

Rodders53

It is one of these TF1 Antifreeze Valve - Fernox UK  may be worth reading the installation instructions etc.,.

Has it been especially cold overnight recently?

If/when it operates there will be more than a small puddle!!  

I'd guess it may have developed a fault.  Consult your installer-maintainer if no-one here has better advice / knowledge.

the_lunatic_is_in_my_head

Rodders53 said:

It is one of these TF1 Antifreeze Valve - Fernox UK  may be worth reading the installation instructions etc.,.

Has it been especially cold overnight recently?

If/when it operates there will be more than a small puddle!!  

I'd guess it may have developed a fault.  Consult your installer-maintainer if no-one here has better advice / knowledge.

Thanks very much for replying, yes it has been frosty over night (cars were frozen this morning) so perhaps it's doing what it should? 

Possibly completely unrelated but we were bleeding the rads yesterday (3 of them had a lot of air but we haven't bled them since it was installed last year). 

I'm a bit confused about the set up but I think; we used to have a woodburning stove with a back boiler and the water that went through the stove went through a coil in the cylinder with that coil heating the hot water for baths, etc and then went round the rads.

I believe this system is the opposite in that the water that goes through the heat pump is the water in the cylinder which in turn heats up the coil for rads.

If that is correct the water that is leaking from this value is replaced by the mains and the air is the rads is completely unrelated? 

Sorry just to edit again, the control panel says the outdoor temperature is 11 degrees and the value should be opening at temperatures of less than 3 and the water is trickling out wen the pump is running so it would appear the valve has possibly failed? 

QrizB

the_lunatic_is_in_my_head said:

If that is correct the water that is leaking from this value is replaced by the mains and the air is the rads is completely unrelated?

I can't speak for your setup but normally the water in the primary circuit of the heat pump would be the same water that's inside your radiators.

the_lunatic_is_in_my_head said:

Sorry just to edit again, the control panel says the outdoor temperature is 11 degrees and the value should be opening at temperatures of less than 3 and the water is trickling out wen the pump is running so it would appear the valve has possibly failed? 

As I understand it, if the antifreeze valve opens as intended it'll dump the entire contents of your primary circuit. If it's dripping/trickling, it sounds more like a leak.

the_lunatic_is_in_my_head

QrizB said:

I can't speak for your setup but normally the water in the primary circuit of the heat pump would be the same water that's inside your radiators.

Thanks QrizB, so if it is the water in the rads is it getting refilled somehow? 

QrizB said:

As I understand it, if the antifreeze valve opens as intended it'll dump the entire contents of your primary circuit. If it's dripping/trickling, it sounds more like a leak.

Sorry if I misunderstand how everything works but wouldn't that leave you with a heat pump running with no water in it? 

Rodders53

IF the water gets down to 3 C that valve will open and dump all the water from the system... It is to prevent freezing damage.  Water will (should) not be replenished automatically. More inhibitor may need adding if a substantial volume has been lost (and air bled out).

Check the HP pressure gauge to check if it is low.

NB it may be 11 now but lower overnight?
Here my weather station says 18 C outside now and 11 C was minimum overnight.

That valve has signs of historical if not current weeping leaks to my eyes (but a plumber on site would be more certain).

Sone HPs have a 'buffer tank' store for the circulating water in the house others don't.  Your installers would know and in an ideal world would explain and leave manuals and design data... few do.

QrizB

the_lunatic_is_in_my_head said:

QrizB said:

I can't speak for your setup but normally the water in the primary circuit of the heat pump would be the same water that's inside your radiators.

Thanks QrizB, so if it is the water in the rads is it getting refilled somehow? 

As above, no it shouldn't be automatically topped up. There might be a filling loop, a bit like a combi boiler?

the_lunatic_is_in_my_head said:

QrizB said:

As I understand it, if the antifreeze valve opens as intended it'll dump the entire contents of your primary circuit. If it's dripping/trickling, it sounds more like a leak.

Sorry if I misunderstand how everything works but wouldn't that leave you with a heat pump running with no water in it? 

The heat pump should have a pressure switch (or flow switch?) so it won't run if the primary circuit is empty.

the_lunatic_is_in_my_head

Rodders53 said:

IF the water gets down to 3 C that valve will open and dump all the water from the system... It is to prevent freezing damage.  Water will (should) not be replenished automatically. More inhibitor may need adding if a substantial volume has been lost (and air bled out).

Check the HP pressure gauge to check if it is low.

NB it may be 11 now but lower overnight?
Here my weather station says 18 C outside now and 11 C was minimum overnight.

That valve has signs of historical if not current weeping leaks to my eyes (but a plumber on site would be more certain).

Sone HPs have a 'buffer tank' store for the circulating water in the house others don't.  Your installers would know and in an ideal world would explain and leave manuals and design data... few do.

Thank you, I see so it's not the outside temp but the water temp that is triggering the value, that makes sense.

Some Googling suggests the valve should dump the water out the bottom and the bit on the top (where the water is coming out) is called a vacuum breaker (don't understand what that does).

If the water doesn't fill up automatically is it a manual thing to add the water or a on/off valve somewhere? 

Typical to occur on a weekend as everything is closed but will call the installers on Monday. 

I don't think we have the buffer tank (there is just 2 expansion tanks). This is the pressure gauge under the expansion tank that feeds off the flow and return between the cylinder and heat pump:



There's a second gauge on the pipework around the cylinder:

 

I'm guessing that is low? 

the_lunatic_is_in_my_head

QrizB said:

The heat pump should have a pressure switch (or flow switch?) so it won't run if the primary circuit is empty.

Makes perfect sense  

QrizB said:

As above, no it shouldn't be automatically topped up. There might be a filling loop, a bit like a combi boiler?

Yes it appears there is a filling loop which I opened to push the pressure up to 1.5 bar (this pushed the pressure up on the expansion tank too), bled the rads again and we are back down to 1 bar. 

The vacuum breaker seems to open when there isn't enough pressure in the system so it's possible bleeding the rads but not using filling loop after has caused the vacuum breaker to do what it is supposed to do. 

I'll wait a while to ensure the water in the system has cooled, bleed the rads one more time and get the pressure up to 1.5 bar and (fingers crossed!) see if water stops coming out of that vacuum breaker. 

Thank you both for taking the time to reply, very much appreciated   

matelodave

The vacuum breaker is there to allow air into the system when the valve opens otherwise it would not be able to dump all the water.

Your pressure gauges are indicating that the pressure is less than 1 bar - normally the system would be pressurised to around 1 to 1.5 bar, so you've definitely got a loss of pressure caused by water leaking.

As others have said, the water in the heating circuit and hot water tank coil will be separate to the stuff you drink and wash with. There should not be anything that allows the system to automatically top-up the system.

That is usually achieved manually with a filling loop connected between the incoming mains and the heating circuit with a manual non-return valve and a flexible pipe (which generally should be left disconnected to avoid contaminating the mains water

As @QrizB says there will be a flow switch that will stop the heatpump if the flow is restricted, either by lots of TRVs closing or insufficient water in the system or if the pressure drops below a safe level