gas heating pressure problem

[kieran5405]

Hi,

I have just bought a new house and, let me say, am very poor at DIY, but I am trying to learn.

For simplicity, I have taken 4 photos of my gas heating set up and posted them on a kodak share site. This will hopefully make it easier for people to see what I mean.

My gas comes from calorgas.

The gas heating has a pipe from which excess water flows if the pressure is to high. this pipe is steadily flowing water when the heat is on and the pressure seems to generally be at about 3 when the gas is on. I have tried to readjust the gas pressure but am not sure how to do this, and the changes i make seem to have no affect.

you paste the above link into a browser, or click on it if that works, you will see a slideshow of 4 photos (use arrow to go through each).

the first photo shows the gas boiler (i think thats what its called). there is an on-off-reset switch, then another switch, then a dial which here shows the level at about 1.5.

the next photo shows another dial which also has a reading of 1.5. On this dial is a knob - i have labbelled A - and a screw - which i have labelled B. I know this controls the pressure but I can not seem to make any change to the system. I tried turning the screw to the '-' and '+' position but no joy. How is this supposed to control the pressure?

The third photo shows the control panel where i turn on the heating. Are you supposed to have the heating on or off when you are changing the gas pressure.

Is there something you are syupposed to do like turn the switch in photo1 to reset and then change the pressure in photo2.

Any help or clarification on how all this works would be greatly appreciated.

The 4th photo is a manual override switch - i do not know what this does.

Any help greatly appreciated.

Kieran

[Aidan]

It is a gas boiler. What make & model? You can usually get the instructions on-line if you haven't got them. The dial is a pressure gauge showing the pressure of water in the heating circuit.

That looks like a Caleffi water Pressure Reducing Valve, with a pressure gauge showing the downstream water pressure in bars. Turning the screw will alter the pressure & flow rate of water coming out of your (cold?) taps, it doesn't affect gas pressure (well I hope it doesn't). I don't know what 'A' does, I'll have to go see.

Don't worry about gas pressure, it's preset & you shouldn't have to ever touch it.

Is there a separate hot water storage cylinder? . This is for domestic hot water (DHW) which you use for washing & laundry and is separate from the water in the heating circuit, mentioned above.

That a Horstmann heating controller/programmer, turns power on to the boiler when you want it available. I think the H37 is a 3 channel programmer, i.e., it operates up to 3 zone valves which control the flow of heat ( typically upstairs heating, downstairs heating & the hot water storage cylinder heat).

No.

That's a zone valve (I Think). The white plastic box is the motor, operated by the programmer. It's fixed to a brass valve connected into the pipe which turns the heating water on/off.

The dripping pipe is probably from a pressure relief (safety) valve on the heating circuit. There is an expansion vessel on the heating circuit containing some air; when the heating water is hot it expands and it compresses the air in the expansion tank. It is probable that the expansion vessel needs recharging. I'd suggest you get a contractor to do it now, but it's easy & you could do it yourself when you've worked out the system. You'd normally set the heating pressure (pressure gauge on boiler) to 1 bar with the system cold. It will increase when the system is hot. The pressure relief valve usually discharges some water at 3 bar or 3.5 bar to limit the pressure.

[Ed Sirett]

Take a look at the sealed CH FAQ.

[Aidan]

snip drivel

Could be an earlier version of one of these;

be a pressure reducing valve with a pressure relief (safety) valve. More pics please. Any writing on the end of the knobs? Use a mirror to see. You need to trace the dripping pipe and see where it goes to; into the boiler or into this thing?

[kieran5405]

Hi guys,

Thanks for all feedback.

The gas boiler is a Vokera Mynute 16e GPL.

On the pressure reducing valve - which has a knob you turn on one side (called 'A' on photo) and a screw on the other side 'B'. There is the word KRAMER wrote on the 'B' side. I cant see any other distinquishing marks on the pressure reducing valve.

I read Ed's article about the sealed heating system and could not find the 'filling point'. The 'discharge pipe' is located on the underside of the gas boiler which is located in a utility room. I see from the article that this is sometimes located outside but in my case it is located inside. It is from here that the water drips when it hits 3 on the bar. When this water is coming from the system is this bad for the system i.e. is it damaging the radiators or the boiler?

Aidan. I am not sure about this, I probably should know this but i could not really see anything. There is nothing else like a cylindar in the utility room and the hot water in the kitchen taps is heated from the water setting on the Horstmann heating controller/programmer. The other two seetings are for the lower and upper floors as you said.

So based on these details, is the water the result of the pressure reducing valve not been correctly set. I can loosen Knob A on itand loosen the screw B - should i be doing this - and which way. Or is it the expansion valve that needs recharging - and how would i do this.

Thanks again for all help.

[Aidan]

That is a system boiler (not a combi). You'll have a hot water storage cylinder in a cupboard somewhere. It's usually about 3' tall & it would look like the one here;

may be an unvented cylinder (supplied by the mains water, rather than from a water storage tank in the loft), because I'm not sure what that pressure reducing valve is for. If that is the case you really need to check that it's correctly set.

Don't know of Kramer, B, I think, adjusts the outlet water pressure. I suspect A is a pressure relief valve, in which case there'd be another pipe connection not visible in the picture. I've never seen one like that.

It sounds like the boiler pressure relief valve, which is probably set to discharge water at 3 bar and is doing just that.

It sounds like there is a filling connection between the boiler and the mains water which has been left connected and open. Usually in the UK, a direct connection is not allowed, so when the pressure relief valve has discharged a litre or two, the pressure drops too low when the system is cold and the boiler will lock-out and won't then restart.

The water fill connection might have been left connected because there's a small leak somewhere, which would otherwise cause regular boiler lock-outs. I think you really need to get someone to look at it for you. Although it's not difficult, but you need it sorted before it causes any damage and it's not something you can reliably diagnose over the internet using the description provided by someone who doesn't know the names for all the bits.

[Ed Sirett]

The filling point, may be integral with the boiler. The discharge pipe is very wrong and this means that the installer was a pillock so other stuff may be wrong too.

Reason for the pressure going to 3 bar are given in the FAQ. Trace where all the pipe go. If all this is getting beyond the OP he should get in some help.