Poltergeist in the central heating system!!

balkanhawk

Hi all,

Im beginning to think that my central heating system is possessed. Here are some basics;

> Two thermostats - 1 upstairs, 1 downstairs.
> Gas boiler - no second tank in the attic.
> Pressure gauge on boiler reading 0.1 Bar when on.
> Two valves upstairs that activate with the thermostats.

Right here is my problem. Part of the downstairs circuit will not switch on at random times!!

The boiler is ON and the downstairs thermostat is ON. You can fry and egg on the radiators in the kitchen. The ones in the hall and livingroom are stone cold (another day they will work!). Ive bleed them loads and there appears to be no air. The water sprays out too so it looks like there is pressure.

Anyone any suggestions or do I have to call in the priest?

FS

Sparkpea

you could call a priest but you'll likely get more than you bargained for.

your system pressure should be around 1.0/1.2bar not 0.1. the more you bleed the rads the more u need to top this pressure up. put it up to 1bar then try the heat - this may cause some radiators to be strange with heating if theres not enough pressure in the system.

i think thats one of your problems, the other is that the motorised valve is faulty and this is why it wont always switch on downstairs - quick fix is there should be a lever on the valve that you can get to manual so the valve is always open and see if it works ok when its set like that for a few days - if so then u need a new valve head.

balkanhawk

Cheers for the pointers. How do i put pressure in the system? I actually had to change the valves around as the downstairs thermo was controlling upstairs when we moved in!!

Sparkpea

there should be like a braided chrome hose near a pressure gauge (if installed correctly). could be near the boiler, in the hot press or even in the loft. opening a valve on it will put mains pressure into the system and the gauge will rise.

im gonna hit the hay its been a long day but im sure fingers mcgee or someone will be about to help you out if im not making any sense - all the best!

balkanhawk

Well the pressure is definitely below .5 bar. I cannot for the life of me find the filling loop.

The boiler is a Vokera Mynute 14e. I found the manual for it and shows how to do it but I have a problem. There are 4 pipes feeding into the bottom of the boiler. Gas, inflow, outflow and the mystery pipe!! Im guessing this is the filling pipe.

If this is the pipe does the valve have to be corrected to the mains as I will have to pull the kitchen apart looking for it?

Pete67

Your mystery pipe is most likely a discharge pipe from the pressure relief valve in the boiler.

It is possible that the system is filled from the cold water starage tank in the attic via a check valve (One way valve). This is quite common, although not ideal. If so you will not get 1 bar or anything close to it at the boiler pressure gauge.

Do you have thermostatic radiator valves on the rads, they sometimes stick closed and prevent the radiator working when it should. Remove the head and check if the pin in the centre of the valve is up (valve open). You should be able to press it down carefully (to close the valve) using a coin or something similar and it should spring back up immediately you let go. The TRV heads can also fail.

Buford T Justice

There should be another pressure gauge somewhere in the house and not just on the boiler (I'm not too familiar with the gas boilers). If the system is only filled from the tank in the attic, then you would always have had this problem

Have a look for you're expansion vessel, like the one below. It could be around this somewhere.


It could be up in the attic either, or the hot press. If you want, post a pic and we can tell you if its there.

balkanhawk

Right gents (or ladies),

Below is a picture of the innards of the boiler ( i downloaded the installation manual). Dont worry i isolated the boiler and just took a picture!




The pipe with the red nut is my mystery pipe. It has 8 bar written on it so im assuming that it could be my missing filling valve. Anyone know how these types of valve work. There is a little black clip (it fell off when i opened the cover) that clips into the metal protrusion at the centre of the red plastic bolthead.

Fingers - I have not seen one of those in my house or attic. Where would they usually be located as i could be blind?

Have a good Xmas by the way!!

Bruthal

Fingers McGee wrote: »

There should be another pressure gauge somewhere in the house and not just on the boiler (I'm not too familiar with the gas boilers). If the system is only filled from the tank in the attic, then you would always have had this problem

Have a look for you're expansion vessel, like the one below. It could be around this somewhere.


It could be up in the attic either, or the hot press. If you want, post a pic and we can tell you if its there.

If the pressure gauge is on the boiler then the expansion vessel is probably in the boiler housing as well if its a system boiler.

balkanhawk

Didnt realise this picture was so small. This link should be bigger;

http://picasaweb.google.com/lh/photo/up4uLitHbbR6UYBNwbKSK4Bzsg5C88mzO4qNl96wLkY?feat=directlink

That vessel could be in the tank.

Could that red valve be a pressure safety dump valve and not the filling valve?

Buford T Justice

Not sure, Gas isn't my thing really. Whats that braided silver pipe at the top of the pic? Can we see both ends?

Bruthal

balkanhawk wrote: »

Didnt realise this picture was so small. This link should be bigger;

http://picasaweb.google.com/lh/photo/up4uLitHbbR6UYBNwbKSK4Bzsg5C88mzO4qNl96wLkY?feat=directlink

That vessel could be in the tank.

Could that red valve be a pressure safety dump valve and not the filling valve?

It looks like the pressure release valve in that pic.

heinbloed

Could that red valve be a pressure safety dump valve and not the filling valve?

Yes.
It is a pressure release valve, the red colour warns against interferences with it.
It would release pressure in emergency cases and can be used as well to drain the boiler. But not as a standard method, these valves have the tendency to leak... There should be a little lever joined to the brass niple, it seems to be missing.When pushing or pulling this missing lever the water will be released.

balkanhawk

Shoot, and I thought it was the solution to my problem! Back to the drawing board so.

I popped into the neighbours house and his pressure is 1.2 Bars compared to my 0.2 Bars.

I'll take the hot press apart and take some pics. It does look like the control room of a steam engine with all of the piping and red taps!!

Have a good Xmas all and enjoy the day. Think I may blame burning the turkey on the boiler...