Advice on heating in a new build property

[slacky]

Hey guys

looking for abit of advice on my heating system in a house I’ve just moved into. Last week I had to bleed a few radiators which I thought was normal but today I’ve had to go round bleeding them again and there was quite abit of air in them. How often should they need to be bleed? The down stairs toilet needed bleeding first time round but now it’s stone cold but doesnt need bleeding. What could be wrong with this? Also a few radiators are hot to touch but if I put my hand over the top it doesn’t feel like much heats coming off them and lastly for a new build property it’s costing anything from £4-6a day for gas and the heatings only on a few hours a day but doesn’t seem to reach temperature. For a new build property it seems abit excessive my old house was built In 1960ish and didn’t cost this much to run.

any help would be appreciated

thanks

 

[slacky]

Yes the boiler goes to 00 and there’s 16 radiators in the whole house. I’ve been round and added up all the kw for the size and type of radiators and it comes to 8.7kw so we’ll in the boiler capacity
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Sorry my mistake on both radiators on the top floor where the stat is there isn’t any trvs on them

 

[Scott_D]

Have you checked the heating system pressure?

 

[king of pipes]

Hmmmm i would say your boiler is undersized 16 rads and a Tribune cylinder is alot for a 15kw ideal i was expecting around 8- 10 rads max

 

[garygvl]

Hmmmm i would say your boiler is undersized 16 rads and a Tribune cylinder is alot for a 15kw ideal i was expecting around 8- 10 rads max

Yes the boiler goes to 00 and there’s 16 radiators in the whole house. I’ve been round and added up all the kw for the size and type of radiators and it comes to 8.7kw so we’ll in the boiler capacity
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Sorry my mistake on both radiators on the top floor where the stat is there isn’t any trvs on them

are you on 3 floors with boiler on ground floor and cylinder on top floor

 

[slacky]

are you on 3 floors with boiler on ground floor and cylinder on top floor

Yes the cylinder on the top floor just outside the bedroom

 

[garygvl]

Yes the cylinder on the top floor just outside the bedroom

tbh 15k on new builds is fine with level of insulation running 15 rads see it all the time. I know you shouldn't have to do this but if you go round all the rads make sure the lockshield valves are fully open. turn off the HW then turn both heating stats on and make sure pump is on max setting then turn all the rads off except one, run this rad for a minute or so so you know all the air in the pipwork has been cleared, go to next rad turn this one on then go back to previous and turn it off to clear next rad pipework of air. repeat this step one rad at a time till you have been round all the rads. turn system off and vent all rads and check system pressure. open all rads to max setting and run boiler with HW and both heating zones on and see if all rads get hot. if not its a balancing issue which site should sort out. had this so many times where boiler on ground floor being pumped up to top floor then back down to ground floor rads on microbore. pump setting can be sorted after you know all rads are balanced

 

[slacky]

Plumber came round earlier to look at the heating played with a couple of lockshields got the rads warm and then went as I suspected he would. The heating was on from 12 when he turned up and by half 4 it had gone from 15 degreees to 19 degrees so 4 degrees in 4 and a half hours. At 2pm she turned the upstairs stat off because the 2 smaller bedrooms wasn’t even warming up even with the doors closed. And all this has cost £3.50

 

[slacky]

Just wanted to give you guys a quick update. I’ve spoke to the site Forman and he’s getting the company that does all the insulation out to get there isn’t anything cold spots etc as the plumbers keep saying the radiators are hot it’s working fine. I’ve started writing down the times, temperatures and cost every hour of the day. I just wanted to ask if I’ve got theos the right with the boiler usage. Am I right in thinking if all my radiators add up to 8.5kw and the gas kwh is 4.23p then if the boilers running at 8.5kw it’ll be using 35p per hour?

 

[Brambles]

No, you need to convert from gross to net. So at 4.23p /kwhr that equates to £0.40/hr. (multiply your calculation by 1.11).

Having said that, it is unusual ( in my experience) for a gas boiler to operate at full capacity for a prolonged period unless it is heating a swimming pool or the outside temp is consistently below -2 degrees C . This winter has, to date, been unusually warm - my gas bill for heat and water (in Oxon) is minimal ( £2.90 /day) for a 27kw system.

In the current market you should be paying around 2.7p per Kw (inc vat) for gas - Utility Point are around 2.45p per Kw. Gas prices are falling quite rapidly at the moment so be wary of locking into a fixed price deal

 

[Stu-B]

It doesn’t work that way, the gas consumption is based on your boiler KW rating, so yours is 15kw when on max setting, or thereabouts.

 

[slacky]

Is there a way to know how much kw the boiler is running at when heating the rads?

 

[Brambles]

Yes, measure the gas rate at the meter, them convert it to KW. That will give you a snap shot in time of what the boiler has modulated to. Not sure how that would help you though.

Very unlikely, in my view, that there is anything significantly wrong with the performance of your boiler.

You would be better off spending your time looking at heat loss calculations to determine the correct sizing of the radiators and insulation of the property.

 

[Kernowplumboy]

Is there a way to know how much kw the boiler is running at when heating the rads?

Are your room stats calling the right way . Ie downstairs stat turns on downstairs upstairs for upstairs ?

 

[centralheatking]

Yes the boiler goes to 00 and there’s 16 radiators in the whole house. I’ve been round and added up all the kw for the size and type of radiators and it comes to 8.7kw so we’ll in the boiler capacity
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Sorry my mistake on both radiators on the top floor where the stat is there isn’t any trvs on them

16 Rads total 8.7 kw are you heating a dolls house. centralheatking

 

[slacky]

All radiators apart from 2 are k1’s and the other 2 are k2’s I’ve been round all of them and took the measurements then got the kw per radiator from the stelrads website which adds up to 8.7kw

 

[centralheatking]

All radiators apart from 2 are k1’s and the other 2 are k2’s I’ve been round all of them and took the measurements then got the kw per radiator from the stelrads website which adds up to 8.7kw

I have installed loads of heating systems since 1980 until a few years ago but because of my business in plumbing and heating keep up or even ahead. Do not be fooled its a case of emporers clothes the system looks good maybe just meets modern regs etc. in reality my last gaff had 30kw over 3 floors and 14 or so rads and guess what I could turn it down ! wait till we get a real cold blast. get some more kw in or buy some electric convection heaters when they are cheap after Easter. centralheatking

 

[king of pipes]

Sorry Slacky but as CH KING has said you havent got enough kw . Kop

 

[slacky]

Do you mean the rads aren’t big enough for room sizes ? If I’m honest I did do a couple of btu calculations on a web site with a couple of rooms sizes and it did say they was big enough not by a lot though

 

[king of pipes]

You cannot raise the tempreture in the property to a comfortable level even after hours of running the system the boilers to small in my opinion, the rads may well be just about adequate but only if you can get enough heat into them which you are struggling to achieve . Kop
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Isolate 50% of the radiators and see if you can get the downstairs up to temperature. ?

 

[gmartine]

Just what I was going to say, on a cold day turn off/down one of your zones and see if the remaining zone gets up to temp then do then do the opposite and see if the other zone gets up to temp. If both zones get up to temp individually but not together you have your answer, I'd also check when your cylinder is calling for heat.