Pressure droping on boiler

[pinheadplanet]

Hi

Last Monday in an attempt to push through any blockage in the DHW heat exchanger I flushed the system by opening the drain valve on the rad and opening the mains feed to the system at the same time (told to try it by my plumber as the DHW was running hot cold). Pressure went up to 3 bar whilst I was doing this.

This didn't work so I then took of the DHW heat exchanger and cleaned it out with DS3 for a few hours. This did work and we have lovely hot showers again (hotter in fact than before the clean).

I set the system pressure back up to 1.4 bar, bled the rads and thought that would be that.

having got home last night (thursday) i notice the pressure was down to 0.7 bar. I checked the rads to bleed them and a little air came out of the highest rad. I filled the system back upto 1.4 bar last night this morning it's back to 0.7 bar.

There's no leak in the boiler where I took off the HE or coming from the Pressure Relief Valve.

What's going on? Does this mean I have a leak in the system or can it be something else?

If it is a leak I vaguely remember seeing chemical leak sealers when I was looking at sentinel/fernox products, are these any good?

Cheers

Halstead Ace High Combi.

 

[easyflow]

No leaks, Then check out your boilers vessel.
Thats Expansion vessel.

 

[pinheadplanet]

What's that and where is it?

 

[pinheadplanet]

I'e just realized that there is a little bit of a puddle under what i would have called the 'overflow' for the boiler outside on the floor. It's difficult to know how much water has come out of there as it's raining now, but I've put a 2 litre bottle under the pipe to see what it collects.

Further to that I've now realized that this is the pressure relief pipe! The other day before I done the repair to the DHW HE the boiler manufacturer said I test if there is water in the appliance by turning the pressure relief valve, situated inside the boiler, a quater turn and water will come out of it if there was water in the appliance. He also told me that these valves don't always sit back as they should, after you turn them. I said I would leave it alone in that case but I just couldn't help myself and I gave it a little turn and it dripped a little.

Does it mean that if the valve inside the boiler doesn't shut closed properly that it will drip inside the boiler (that was my understanding) or that it will divert the water out through the pressure relief pipe to outside?

I've got the heating on now and the PRpipe IS hot after the valve, so I would assume it's getting hot water through it... ???

Can it be that the valve is open and my water loss is just going out through the PR pipe and not perhaps through a burst seal in a pipe under the floor as I originally thought?

 

[skowi187]

yes it discharges outside through the pipe the boiler insides will be fine if the blow-off pipe is installed correctly. should either run to waist height or turn into the wall to avoid scalding when discharging. you need to replace the pressure relief valve and next time when some1 says dont touch it.... DONT lol

 

[MANDATE]

Remember me telling you about that?.

 

[pinheadplanet]

To try to check if it was the pressure relief pipe l Stuck a bottle on the end of it and it seems to have collected a bit of water in it, so I guess that could be my problem.

Am I gonna do any damage to the boiler by running it on 0.7bar for a few days while i sort out getting a new valve?

Remember me telling you about that?.

Well partially, unfortunately I have some strange disease that doesn't enable me to remember certain things, but I knew I had heard it from some other source than the boiler manufacturer.

So essentially I'm safe - I was concerned that I had burst a pipe under the floor! I guess it's fairly easy to change the PRV.

I assume if I turn the PRV a quarter turn it will drain down the boiler out through the pressure relief pipe, then i can change it.