Worcester Bosch HE40+ and low central heating temperature

[Worzel]

Hi,

I've tried a search on this but couldn't find any info.

I've recently had a Worcester Bosch HE40+ (condensing combi) fitted, boiler was chosen due to the hot water flow rate and good feedback from people with other Worcester boilers. The old storage tanks and hot water cylinder were removed at the same time.

The problem I have is that the temperature in the house takes forever (up to 8 hours) to reach the setpoint on the room stat (Worcester TR2).

The engineer that fitted it said that he thinks the radiators are undersized for the house. However, our old Potterton flamingo conventional boiler was able to heat the house up quite nicely.

Has anyone come across a similar issue?

Any ideas are gratefully received as I've been unable to get through to the helpline so far!

Cheers

Jon

 

[kevplumb]

is the gas supply to spec
recently fitted a 35 he in a house with 4 floors and 22 rads takes approx 1 hr to heat up to 19 deg
are the rads getting hot or warm

 

[Worzel]

KP,

As far as I can see the gas supply pipe to the boiler is 28 mm until around 30 cm from the boiler when it reduces to 22mm.

Rads are getting fairly hot but not to the point where you can't keep your hand on them.

Jon

 

[kevplumb]

is the flow from the boiler to hot to hold

 

[Worzel]

Thanks for the help.

Will check in the next couple of hours and get back to you. Stuck in work at the moment.


Jon

 

[Dustyy]

Kevplumb,
I am having a 35HE+ installed at the w/e - should the gas pipe be 22mm or 28mm? Run from the meter is about 3m plus 5 to 6 bends.
Am I correct in thinking that TRVs should be installed on all radiators bar the one where the thermostat is to be fitted? If so, I take it this rad will operate as the 'by-pass' rad? I have read elsewhere that installing more than a third of the rads on a condensing boiler system will reduce its efficiency (i admit it - it was a Shed brochure )

Cheers

 

[kevplumb]

gas pipe should be ok
trvs are ok exept where the roomstat is
i left the bathrooms off as well
dunno about the rest the longer you can keep it condensing the cheaper it is to run
if you only install a third of the rads on the condenser what do you connect the rest to

 

[Dustyy]

sorry, meant to say this 'guidance' suggests that only a third of the rads should have TRVs, the rest just normal lockshield valves.
My other worry is the siting of the flue. The boiler is to go in the old chimney hearth space in the kitchen which means that if the flue were to be sent out horizontally off the top of the boiler then it will be at about chest height outside. I am considering trying to take the flue up the existing chimney to a height of say 2.5m so that it is out of harms way. Am I being a little over cautious and will the guard dissipate the vented emission enough if left at chest height?. I have seen a mates 30HE emission and it seems to come out at quite a rate

 

[kevplumb]

they do throw out quite a plume
just take it up another metre should be ok

 

[Dustyy]

Thanks, I'll discuss with the plumber and try and convince him the extra work is needed

 

[Worzel]

Right, I've checked and the flow from the boiler is hot. The display on the boiler says that the flow temp is 88DegC. Having watched the boiler run through a cycle it starts up the burner when the flow temp is 53DegC runs for around 1 min until the temp reaches 82DegC and then shuts the burner down. The burner stays off until the flow temp reaches 53DegC again (approx 90 seconds) and then starts the burner up again.

The thermostat is has now been set at 23 for two hours and the room temp has only just reached 18.5DegC.

Does this sound right? I would have expected the burner to stay on longer and hence cycle less.

Jon

 

[kevplumb]

sounds like flow balancing problem
get the installer back

 

[Worzel]

Cheers Kev,

Had a feeling I'd need to.

Off to find my beating stick as he's been back twice already.

Jon

 

[kevplumb]

just to give you an insight the one i fitted dosent turn off it just modulates to suit the load
mind you its a large load

 

[shaneo]

its got to be a flow problem, there isnt really any excuse if the system used to work fine berofe this was fitted
and also condencing boilers should heat the house up full really really quick,
the pump is set to speed 1 is it?
if so switch it round to 3, its worth a try