New rad - single to Double

2012paddy2012

Hi have a viessman boiler - pressure always between 1 and 2 when off - after the plumber changed the single rad to a double in the kitchen - he ran the boiler for few mins - Said leave it on for 20 which I did -

I noticed when I turned off the heat after about half an hour I had checked all the rads around the house including the new replacement- all pipping hot - was delighted as the kitchen was always cool - it’s lovely now -
The pressure was over 2,- I told him and he said it’s ok between , 1.5 and 2.5 - that’s ok -
However the guy who services it - he did it last week - said it should. Always be between 1 and 2 - occasionally it would drop slightly below one - and he showed me how to increase the pressure slightly - by turning knob in hot press - which I did from time to time -
Now it’s just below 3 and a “ red” icon which I take to mean “ danger” or be aware - I wonder what could the reason for the pressure to increase , when no issue prior to this replacement rad being fitted !?

davebuck

Are you sure the knob (valve) is turned completely off if its not the pressure will keep rising or else maybe the valve is now passing which will need to be replaced. The fact you need to top up from time to time might mean you have another issue....

Lenar3556

2012paddy2012 wrote: »

Hi have a viessman boiler - pressure always between 1 and 2 when off - after the plumber changed the single rad to a double in the kitchen - he ran the boiler for few mins - Said leave it on for 20 which I did -

I noticed when I turned off the heat after about half an hour I had checked all the rads around the house including the new replacement- all pipping hot - was delighted as the kitchen was always cool - it’s lovely now -
The pressure was over 2,- I told him and he said it’s ok between , 1.5 and 2.5 - that’s ok -
However the guy who services it - he did it last week - said it should. Always be between 1 and 2 - occasionally it would drop slightly below one - and he showed me how to increase the pressure slightly - by turning knob in hot press - which I did from time to time -
Now it’s just below 3 and a “ red” icon which I take to mean “ danger” or be aware - I wonder what could the reason for the pressure to increase , when no issue prior to this replacement rad being fitted !?

How often do you have to top it up out of interest? It should be at about 1.2 when the system is cold.

In answer to your question, the system could be overfilled, (see above) or the expansion vessel may be undersized or impaired. The double panel radiator would have added slightly extra water volume to the system which may have highlighted the expansion issue.

2012paddy2012

davebuck wrote: »

Are you sure the knob (valve) is turned completely off if its not the pressure will keep rising or else maybe the valve is now passing which will need to be replaced. The fact you need to top up from time to time might mean you have another issue....

Indeed , when the service guy was here he asked how often I had to increase the pressure since he was here last , which was about 15 months ago - I said maybe three times - quick turn of the value did it -he said he saw one or two drops of water under the boiler unit - I asked how could that be - he said with constant vibration of the boiler on/off - can very slight loosen odd fitting- he is qualified / certified service man - he tightened them- I’ll ask the plumber if he definitely switched the valve back to the way it was - I can’t recall him returning to the hot press after re pressurising the replacement rad - he may have

2012paddy2012

Lenar3556 wrote: »

How often do you have to top it up out of interest? It should be at about 1.2 when the system is cold.

In answer to your question, the system could be overfilled, (see above) or the expansion vessel may be undersized or impaired. The double panel radiator would have added slightly extra water volume to the system which may have highlighted the expansion issue.

Thank you , I’ll check

LenWoods

Just to note: The pressure will increase when the water inside is hot,

2012paddy2012

LenWoods wrote: »

Just to note: The pressure will increase when the water inside is hot,

That’s very interesting -I see this morning well now it’s just below 2 - usually midway between 1 and 2-
I checked the hot press the filler valve was back closed all ok there - as you say it did increase up nearer to 3 alright when heating on - I think it’s probably ok - but I may have that expansion thing in the hot press - needing looking at - I’ll keep an eye - I think three modern boilers have cut out. - if anything goes wrong - that was more my concern really - thanks for all the help

2012paddy2012

LenWoods wrote: »

Just to note: The pressure will increase when the water inside is hot,

Seems he fixed it - took water out of it and pressure back to normal !