valiant 837 boiler temp? mis sized radiators

[Foxyuk]

Well guys after using same engineer for 20 years patience run out

My temp output on boiler I have increased from 56 to 62 for cold weather is that enough?? Max is 75 on dial

New system amd rads pipes etc all fitted with a siemens thermostat. With receiver. From temp of 16 degrees in lounge takes well over 3 hours to reach 20 degrees. Its 4.57 m x 4.11 m with bigbay windows approx 10 feet by 4 feet, there is cellar under house and most rooms are2 external walls

This room has delonghi double rad single convector measuring 1400 x 600. With a single 1200 x 400 under bay. Is this room under speced??

Daughter room is directly above boiler in cellar. 4.37 m by 3.4 m with windows about 6 feet by 4. In this room is fitted same delonghi double single convertor however its 1000x 600. U put the thermostat in this room and drops 2 degrees imediately. And lucky if moves up a degree in an hour

All rads are bled etc. Have my rads been seriusly under speced ? I'm in glasgow area if anyone can help. Problem is when u use same person too long they become complacent and so do I

Totally scunnered

 

[doitmyself]

Whack the temperature up to 75C and see what happens.

What method did your installer use to size the boiler and rads?

Which model Siemens stat do you have?

 

[mountainman]

Turn boiler heating control up to 70, that will help.
I've not got rad calculator with me but I'd say your rads are undersized.

 

[Foxyuk]

Will turn to max later. The thermostat with receiver is siemens RDJ10RF. I leave it on at 16 degrees comfort since cold weather and bump it up when in house.

Not the greatest remote never used time programmer

With regards to sizing my impression is he bought them based of years of experience supplying and fitting certainly nothing else.

This guy is that busy it took months to commision system and still not come back for the install money. I have known him foryears but time to change when he does not appear when arranged or answer calls or texts and all I get is really busy when I do get him

Where do I stand with misizing rads etc? Is there not a duty to size them correctly under gas safe

Really looking for closure however I suppose I have the ace as not paid however that's not by choice

I will post sizes of rooms later with rads in the rooms and hopefully someone can help its the window allowance on the calc I am prob messing up, don't want to spit dummy without the facts

Thanks in advance .

 

[doitmyself]

Your boiler may be oversized for heating, so it is continually cycling; this will give long heat-up times.

Use the Whole House Boiler Size Calculator to find your heating requirement. You may have to enter your total window area as it makes some assumptions. You should also deduct 2kW from the result as you have a combi boiler.

Post the result.

 

[Foxyuk]

Your boiler may be oversized for heating, so it is continually cycling; this will give long heat-up times.

Use the Whole House Boiler Size Calculator to find your heating requirement. You may have to enter your total window area as it makes some assumptions. You should also deduct 2kW from the result as you have a combi boiler.






my understanding is that this boiler adjust output accordingly .. i did not adjust the water auto figure

below is the result of the calc as above however does not take into account factors ie the house is 85 years old, sandstone fronted with cavity and rest is solid brick in addition theres a cellar beneath house that is approx 4 feet high.... the windows total area is high as both front rooms have bay windows 6 square metres per room and the rear bedroom is 62 inch x 70 inch (4.31 metres)

my concern is radiators in the 2 front rooms and the rear bedroom

living room is 18.7m2 radiator is double rad single convector (1400 x 600 ) output 7159 btu 2098 watts
single rad single convector (1200 x 400) output 3079 btu 902 watts

daughters room 14.858m2 double rad single convector (1000 x 600) 4114 btu 1499 watts

main bedroom 18.5m2 double rad single convector ( 1200 x 600) 6136 btu 1798 watts
single rad single convector (1200 x 400) output 3079 btu 902 watts

the long rads are under both the bay fronted windows

-----------------------------------------------------------------------------------------
The dwelling type is detached with double glazed windows with wood/plastic frames.
The external walls are cavity, no insulation.
The roof is pitched with more than 75mm of insulation.
The Dwelling is in Scotland.
The following three major contributors to the heat requirement
are all affected by the levels of insulation.
The WINDOW heat loss is 1.80 kW
The WALL heat loss is 3.30 kW
The ROOF heat loss is 1.18 kW
Note down the kW readings (or print this page) then press your
browser's Back button.

If better insulation is possible, make selections with higher levels of insulation,
then calculate again to see the effect on the boiler size required.

By spending money on, say, more loft insulation you may save money on the
price of the boiler, and you will definitely save money FOREVER on your heating bills.
The required boiler output is 11.77 kW

 

[doitmyself]

my understanding is that this boiler adjust output accordingly.

Yes it does, but there is a minimum it can go to. In the case of the 837 it is 12kW

The dwelling type is detached with double glazed windows with wood/plastic frames.
The external walls are cavity, no insulation.
The roof is pitched with more than 75mm of insulation.
The Dwelling is in Scotland.

The required boiler output is 11.77 kW

Ground floor losses are dependent on the floor area and the perimeter length; the fact that there is a cellar does not make any real difference.

Assuming you have fed in the correct data, you will see that the required boiler size is almost the same as the minimum the 837 can produce. This means that, when the outside temperature is higher than the -1C used in the calculation, the boiler will be unable to go any lower than 12kW; it will have to resort to on-off mode, which is much less efficient and can result in the house taking longer to heat up

If you assumed a worst case, e.g solid walls, single glazed windows etc, your requirement would be approx 21kW.

Monitor your boiler and see how often it stops and starts (ignore when it is producing hot water).

Another factor is that the boiler will start at a high output and then modulate down when it realized the water temperature is rising too fast. This can also have a detrimental effect on the rate at which the house heats up.

 

[buckley plumb]

set boiler to max . go into settings and increase to 80 .what size pipes are to the radiators

 

[Nostrum]

If they used -1 in Glasgow you've had it!

 

[vern]

Just get an engineer who knows what they are doing, to set up the system and commission the boiler!.....all the crap about whole house heat calls is just that, and does not apply to combi's as they are exempt, 37Kw is for the DHW, the heating can be range rated via the on board software.....if your still cold when the stat on the boiler is run at 75 deg, swap the single rads for doubles, job done!

 

[vern]

Just to add although you have given you room sizes, the height of your ceilings is a very important factor too especially in older properties....

 

[Foxyuk]

hi guys the height of celings are 104 inches high (8.6 feet high)... i will turn it up to 75 in the morning

"""""set boiler to max . go into settings and increase to 80 .what size pipes are to the radiators""""""

increase what to 80? the max is 75 if u are meaning that, the pipe is plastic with copper tails above the floor ... im sure the pipe is 15 mm

ok anyone know someone hood in glasgow area to sort this once and for all or am i better calling valiant and taking a hit on service charge??

i have checked meter in last 2 days i have used 19 units which is about 220 kw... which is a fair bit for a house thats never over 20 degrees and therm sat at 16.5 comfort the rest of the time.

 

[lame plumber]

get an engineer out to survey your house properly, work out each of the room heat/vent losses properly in order to work out the rad outout required, forget the boiler size as that is easily able to cope and modulate down to the heating output required. If you havent paid yet you have nothing to loose and it sounds to me that they are undersized and you need more insulation to keep the heat in. there are some things you can do on a forum and a survey to plan a ch installation isnt one of them

 

[Foxyuk]

Ok Heating now up at max house is a lot warmer got room thermostat set at 20 degrees arranged for engineer valiant approved to come out a week on Monday his gut instinct is radiator sizes but will not male judgement till seen

With regards to amount of times boiler cuts in and out I don't know as boiler is situated in the cellar against outside wall

 

[vern]

Ok Heating now up at max house is a lot warmer got room thermostat set at 20 degrees arranged for engineer valiant approved to come out a week on Monday his gut instinct is radiator sizes but will not male judgement till seen

With regards to amount of times boiler cuts in and out I don't know as boiler is situated in the cellar against outside wall

Keep us updated, I think it will be the rads and/or insulation to be honest.....won't hurt for vaillant to give it a once over though.....

 

[Foxyuk]

Keep us updated, I think it will be the rads and/or insulation to be honest.....won't hurt for vaillant to give it a once over though.....

no worries . doubt its the insulation as it was only renewed fully 6 months ago... house got refurbed when i purchased , new roof also with the air vents etc.. actuall went up loft for xmas tree and it was freezing .. the walls are brick and lathom plaster mind you majority of the walls been redone and in addition ceiling was framed & dropped throughout by few inch as lathom plaster was poor