High pressure on combi boiler

Hi, I have recently moved house and I think I have inherited a problem with the already installed combi boiler. I am not sure of the model of it, I do know it is made by Radiant. The boiler works fine.....but, in order for the boiler to start, the pressure has to be 2 bar. I am concerned as when the radiators heat up the pressure then goes up to 3 bar. I also know that when the pressure goes higher it stays high....shouldn't the boiler have some sort of release valve / overflow when the pressure gets high? If I didn't know that the pressure was high (and on occasions above 3 bar) I would be happy with the system as the heating and hot water is faultless.

How do I identify the model of the boiler?
Do boilers / heating systems work at different pressures?
Do I have reasons for concern?
If yes, then can I fix it, or do I need an engineer?

Thanks in advance!

do you mean ravenheat ???

pressure release valve should open at 3 bar

is the fill loop disconnected ?

shuoldnt need to be 2 to run is the guage ok ?

No, it is definately Radiant. Today I have managed to find their website and a UK contact.

http://www.radiant.it/eng/assistenza_ris.php?ostato=ENGLAND&Submit.x=39&Submit.y=4

The gauge appears ok, is there a way of testing. When the system is empty, the gauge is at zero.

As long as it isn't firing through the PRV, I wouldn't worry about it too much,

I can't remember a radient model with a gauge, (as far as I remember they all had an electronic display which just tells you if the pressure is between <0.7 / 0.7-2.0 / >2.0)

Check that your filling loop is closed, and not slowly dripfilling the system, (remove the link would be preferable)

I honestly can't remember where the dataplate is on a Radiant, I know a guy who used to be the Radiant service engineer, I'll ask him if I see him for you

Thanks for that!

To be honest, I don't understand why the boiler doesn't fire up until the pressure is nearly 2 bar....anything less and the warning light comes on indicating low pressure.

Is this normal for this Radiant boiler?
If not, how do I stop this low pressure light coming on even at nearly 2 bar?

Either the pressure indicator is reading high or the pressure switch (controlling the LP indicator) is measuring low, or is blocked.

Either way, if you don't know the boiler you'd probably be better advised to Get Someone In who does.

But if you don't live near Bedford (the gaff of the only guy in UK owning up to be a fully-paid-up Radiant service engineer) I guess that could be tricky!

It sounds like either your expansion vessel is flat and needs recharching again! id put my house on it!

you would lose mate

Radient were a bit (read: considerably) crappy to work for from what I remember.

I'd see ph's bet because a flat xvessel doesn't affect the pressure switch, which was your complaint, not the boiler's pressure raising wildly when hot. (at 2bar it should be mainly full of water anyway)

You either have crud in the pipe to the pressure switch which its somhow lowering the pressure measured by the switch, the switch is dodgy and reading the wrong pressure and needs renewing, or the pressure dial is reading incorrectly.

*steals his mates Radient Service Engineer stickers* hell I went through all the bunf they sent him.. thats just as good.. (I still haven't seen him btw )

Your boiler should have a minimum pressure of 0.7 bar not 2 bar, first check your instruments, does the dial show any signs of being faulty at all? does the boiler fire off through the PRV (externally) when it goes over 3 bar of pressure?

if not then suspect the pressure switch, it (if i remember correctly) is a white and metal 3 wire switch on the left of the boiler. (or at least it was on the few I've worked on and in the service engineer bunf)

Nearly all Radient parts are interchangable between models, so it should be fairly easy to get. (thou I've had one with a faulty pressure switch before and it was a bit of a b to get one)

Check in the obvious places for the dataplate, behind the front cover, on the front panel, underneath the bottom of the casing. I _should_ have the manual for it if you can give me the model

The model number is RSF 24 and made in 07/1994. The gauge appears to be working fine but the PRV hasnt let of any presssure at all. I have manually turned the PRV though which worked. Strangley, on the front of the PRV is says "SYR 6 bar" Does that mean it is designed to let out pressure at 6 bar!

on the front of the PRV is says "SYR 6 bar" Does that mean it is designed to let out pressure at 6 bar?

Click to expand...

Yes it does. BUT IT DEFINITELY SHOULD NOT!!!
I don't know how Radiant built their boilers and therefore whether they can withstand 6 Bar. But I DO know that if you put 6 Bar into a radiator, chances are it will distort, leak or go pop!

As far as I know, all Combis have a 3 Bar PRV.

It seems that your's has had the wrong part fitted, making it DANGEROUS.

i have a radiant boiler model rsf 24 in the house i have just moved into,the trouble is when i took of one of the rads to do a bit of decorating i losed pressure on the system . now ive but the rad back on the system is saying the pressure is too low , so ive refeard to the instruction manual and it says to open the filling loop but i have looked high and low and i can not find it , has anyone got any ideas as to where they fit the filliing loop on these systems

Please start a new thread. People will think the earlier postings relate to your problem.