Bleeding radiator Question/Concern

[KateDavison]

Hello everyone.

I have a little question that I hope someone will be able to answer. It might be nothing but anyway! : Basically I used to have a normal boiler with hot water tank and cold water tank. I have a combi boiler now in my new flat. It was already here when I moved in last week.

The problem I noticed is, when I bled the upstairs radiator 2 days ago, water seemed so powerful when it came out, compared to when I used to bleed my other radiators in my old flat.

Is it just me, or is there a problem. I was just curious as to why it seemed this way or if it is normal?

Thanks for your help and for reading my post here

Kate

 

[Nige F]

Hello and welcome . Your combi has water under pressure ( about 1.5bar) in the heating circuit . Your other system commonly had water @ a lower pressure . That`s why it spurts

 

[jackthom]

No there's unlikely to be a problem.

With this type of system the pressure (as shown on the meter at front of the boiler) will probably be a fair bit higher than your old one which had a feed and expansion tank in the loft.

After bleeding radiators you should check the pressure displayed on the boiler and if it's below the mark use the cold water filling loop to repressure the system.

 

[KateDavison]

Thanks

I have checked the gauge and it is between 1 and 1.5


There is another slight issue that I have been trying to find out by searching, if anyone could help?

The hot water "perforamnce" so to speak at the taps is not good. The boiler apparantly (I was told) is very new, Ideal: Logic. (that's the name on it).

When I say poor, I mean not very hot at all.

Any ideas what this could be please?

 

[jackthom]

A combi can't generally supply piping hot water at the same rate as your old hot water tank could, especially when you are trying to fill a bath. As the mains water coming into the boiler is colder in winter the problem becomes worse.

To get really hot water you might have to experiment a bit by closing the tap slightly so a smaller quantity of water is coming through and being heated to a higher temperature.

 

[KateDavison]

Thanks for your replies.

Looking in the boiler booklet, it says could be crossed hot and cold pipes in the fault chart? How can I check this? The water is very very lukewarm. Could this be possible.

 

[jackthom]

I think that refers to the possibility of the cold water supply in a thermostatic shower mixer valve getting back into the hot water supply and diluting it.
I'm not sure if that one's a particularly common problem.

Some things worth checking, assuming the hot water control on the front panel has been turned up high enough.....


While the hot tap is running make sure that the boiler continues firing at maximum power (from the fan/burner noise it makes) and is not backing off to a lower power setting.


With CH turned off for a while, long enough for the pipework at the boiler to have cooled, run the hot tap for a few minutes and see if any of the heated water is leaking into the central heating pipes.

 

[jackecole]

Hi Katie

Is the hot water very low / lukewarm temperature?

As Jack says feel the heating flow pipe under the boiler with the hot tap on, it could be diverter valve letting by.

Also, with the hot tap open, and the boiler front cover removed (2 screws under front and 2 clips), the boiler booklet will explain how to do this - does a little red light, light up on the flow turbine? (the boiler booklet will explain where this is)

Or if it has always done this since you moved in, it could mean the cold water inlet and hot outlet are reversed! If so, try this: turn the valve off to the cold water inlet supply (smaller diamteer pipe) under the boiler. Then, do you know how to re-ill/top up the system pressure? If so, join the rigid fillip loop (built into boiler) and try and re-charge the system. If it still fills, then the pipes are reversed! badly installed/dodgy installed boiler.

There could be other things to check, but would be better of getting a heating engineer in to check and sort these.

 

[jackecole]

also check the hot water dial is turned up fully as Jack said