Vokera compact 24. struggling to heat rads

[plumtect]

Hi am having problems with my compact 24 its runs but take ages to heat rads..starts up runs for 1-2mns then stops sounds like its not pushing it round system..i`ve power flush it out a few weeks back then fitted a new pump and prv valve new thermistors ..dont know to do next heat is traveling from boiler to upstairs rads then back down to sitting room hall and kitchen. up stairs is warm..boilers about 8-10 yrs old..
it may be over worked as i have put 4 double rad in since fitting it
Any one any thoughts.. or do i flush it agian...

 

[McCombi]

Is the flow pipe from the boiler getting hot and return pipe to boiler getting hot enough? Bypass valve on system may be open too much resulting in heat returning to boiler before getting to radiators.
Maybe the radiators haven't been balanced correctly (check site or online to find out how)
Possible that diverter valve faulty and passing heat to hot water circuit and overheating... could be many things, without seeing it difficult to diagnose.

 

[Agile]

Is it a one pipe system?

Balance rads? See FAQ

Tony

 

[plumtect]

Thanks for your replys...is a 2pipe system flow/return no diverter valve!
i `ve being play with boiler ..left it on all day and its bearly warm..
so i`ve closed the return vavle off opened prv valve turned fill loop on an flushed for 4-5 mns then filled to 1.5bar turned it up to max an restarted.....an now its running like it should all rads are getting warm..
so is it a air lock ...blockage...all rads are wide open no trv valve on as boiler works on radiator temp.....but i thinks in the morning it wont do this when i turn it on...
will let you know in the moring ...this rain is not letting up..
Thanks...

 

[kirkgas]

first things first, get a radiator spec sheet and count the load of the system (something you should have done BEFORE you fitted the 4 new double rads)
what is the new out put, is it less than 24kw, if so then the boiler should heat them, try shutting 2-3 rads off, does the boiler work ? if so then its possible you have overloaded it, if not then you have a circulation problem, either air or sludge
the symptoms sound like a circulation problem rather than overloading, so you will need to investigate further, check the water, check the pump balance the system, there is loads you will need to do before we know whats wrong

 

[Whitespirit66]

Not a good idea to use the PRV as an outlet for flushing. It's a pressure release valve.

These have metal to metal valve seats, and debris can get lodged in the valve and make it leak.

Best to stick to a drain off cock if you need to drain/flush.

Untitled

• Whitespirit66
• 29 Aug 2011
• 7

 

[DP]

Not a good idea to use the PRV as an outlet for flushing. It's a pressure release valve.

I always drain from this point as this valve is a safety valve and does get 'stuck' resulting in overpressure. Have seen this happen often. If it leaks, so be it- I carry replacements.

These have metal to metal valve seats, and debris can get lodged in the valve and make it leak.

Can you say which valve has metal to metal seat? Ones I have seen have a rubber boot

 

[Terrywookfit]

Not a good idea to use the PRV as an outlet for flushing. It's a pressure release valve.

I always drain from this point as this valve is a safety valve and does get 'stuck' resulting in overpressure. Have seen this happen often. If it leaks, so be it- I carry replacements.

These have metal to metal valve seats, and debris can get lodged in the valve and make it leak.

Can you say which valve has metal to metal seat? Ones I have seen have a rubber boot

"Nabic"are definately metal/metal seat.

 

[DP]

Terry, are these valves fitted to combination boilers (certainly not found in a Vokera Compact)?

Do concede the point if metal to metal, but then unlikely to stick

 

[Terrywookfit]

I was giving a simple answer to the question.

Can you say which valve has metal to metal seat? Ones I have seen have a rubber boot icon_surprised.gif


I will concede that I have never seen one on a Vokera Compact.