Central heating is slow to heat up house

[nijx]

hello

we recently installed a new boiler (we have a hot water tank & open vent heating system). The boiler works fine as we get hot water.

the heating is ridiculously slow as heating up the rads.
The system was power flushed when they installed the new boiler.

some of the rads take upto 4/5 hrs to get WARM, they DO NOT get hot where it's too hot to touch.

I've bled all the rads & there's no air.

I wonder what people can recommend/ options to try to improve?

thanks

 

[RigidRaider]

What kind of valve is controlling the flow of hot water from the boiler to the radiators?

Who installed the new boiler?

 

[Armo74]

Do all the rads heat up?

Did the system get balanced?

Have the rads got TRV's?

 

[FiremanT]

What kind of valve is controlling the flow of hot water from the boiler to the radiators?

Who installed the new boiler?[/quote]

More to the point, have you asked them?

 

[nijx]

asked the guys who installed the boiler and they said it's fine... but it's not!
was supposedly balanced

TRVs on rads

rads do heat up, but takes a good while and then it's not piping HOT

 

[Dean744PiN5]

Make and model of boiler?

 

[TheVictorian]

Do any of your rads get piping hot and do some get hot before others?

 

[nijx]

Valliant 428 (i think)

rads do NOT ever get piping hot.
I suppose they are at different temperatures (well certainly feel that way)

 

[Dean744PiN5]

28kw's thats a lot of heat, you must have a big house? Sounds like the boiler is short cycling (getting up to temp really quick then shutting off for a short period). Have you watched the boiler does it behave in that way?

 

[nijx]

it's a 4 bed house.

How do i determine if it's 'short cycling'?

Not watched it... rather boring!

I know the water heats up fine though

 

[Dean744PiN5]

Have the timer and thermostat call for heat and watch the temprature on the boiler display. Does it rise quickly (with flame icon on) then start dropping(with no flame icon). Also do a whole house calc to see how much heat your property needs. Here's the link.
http://www.idhee.org.uk/calculator.html

 

[nijx]

boiler spec seems fine for the house

I have left the heating on permanently before and notice it does take a while for the temp to go from c30s to 60/70s.
But once there it seems to stay around the 60/70s

 

[Dean744PiN5]

Thats good, dosn't sound like its short cycling, from the information given. So the problem has got to be with flow, but that could be a number of things. Really you need to explain to your installer again your situation and the fact the heating takes hours to heat up and give him the chance to investigate.

 

[Dean744PiN5]

Also take a look at the circulating pump, does it say 15/50 or 15/60 on the front?

 

[RigidRaider]

What is short cycling and could it explain why our boiler isn't heating the HW properly? The water temp increases rapidly to 83 then the boiler stops, as if the coil isn't taking enough heat out of the HW circuit.