vaillent ecotech 837 using lots of gas and doesnt heat house

[jkcov]

i had an eco tech 837 installed last week and i have noticed that it is eating the gas ie 1.3 units black ones per hour that the heating is on. Also the heating never gets the house warm ie does not go above 19c.
my old potterson flamingo cylinder boiler rated f or g got the house really hot and never used the gas like this ecotech.
Any ideas guys??
No gas leak by the way and new regulator on meter

 

[lightning]

How many rads and sizes of them, has the boiler been range rated, is your has insulated ie walls and loft, what are your trv's set at???

 

[D_Hailsham]

i had an eco tech 837 installed last week

You don't say which version of the Flamingo you had, but the largest one was only 15kW. The 837 is 28kW.

Who decided what size boiler you needed?

 

[Beerlover]

Anyone smell something?........................sure I've smelt it before.

 

[jkcov]

I have 4 double rads 4 single but large ie 600 by 1400 and 2 small rads and towel rad. Total kw of rads 12/13 kw. Not sure of size of flamingo. The guy who installed it recommended 837. Defo no gas leak. Iv just timed how much gas it used to run a bath 5 mins of just hot water resulted in 0.48 unit of gas. My meter is m3 meter with 5 black 3 red digits. Im not sure if he range rated it. Is that done at install? The boiler should lower its heating kw to match the rad needs. I have tried to lower the kw to 13kw on the boiler within the engineer setting but made no difference. I live in a terraced house 3 bed good insulation all round. tvrs on all rads but hall set at 5. Thermast in same place as the other one. Iv worked out that if i used my boiler like my old one ie set at 17/18c in the day and at night and 22c for 1hr in morning and 4 hrs after work i would use 31 units of gas because the boiler would just stay on because it cant raise the temp of the house high enough.

 

[PowerFlushAssociation]

Just maybe:
- Was the regulator changed when the boiler was changed? The old one could have supplied more gas than the meter counted so you only notice now how much the boiler really uses.
- Gas pipe sizes, ok? No debris in gas pipes?

 

[Agile]

Did the installer fill in the benchmark Certificate?

Are you near Oliver Street?

Tony

 

[namsag]

Simple get him back its a boiler issue not a system issue

 

[D_Hailsham]

I have 4 double rads 4 single but large ie 600 by 1400 and 2 small rads and towel rad. Total kw of rads 12/13 kw. Not sure of size of flamingo. The guy who installed it recommended 837.

So you have 13kW of rads trying to dissipate 28kW of heat. The boiler will short cycle (turn on and off) all the time as the return temperature will not fall sufficiently. and the flow temperature will rise too fast. The net effect is that the water never reaches the correct temperature, so the house does not warm up.

The minimum output of an 837 is 12kW, approximately the same as your rads. But you will only need this amount of heat in very cold conditions (-1C outside or lower). In the current mild weather you may only need half of that. In this situation the boiler will have to turn on and off to maintain the required flow temperature. In fact, because your boiler is so oversized it will spend most of its life turning on and off.

Your installer has sized the boiler based on your hot water requirement, without taking the heating requirement into account.

A better choice of boiler would have been either the Intergas HRE 28/24 or the Remeha Avanta 28C. Both of these can provide the same HW performance, but they can modulate down to 7kW and 6kW respectively.

Replacing the boiler is probably not an option, but you can partially solve the problem by range rating the 837. Ask the installer to set the CH output to, say 15kW, using parameter d.0.

 

[Garfeild]

Just maybe:
- Was the regulator changed when the boiler was changed? The old one could have supplied more gas than the meter counted so you only notice now how much the boiler really uses.
- Gas pipe sizes, ok? No debris in gas pipes?

 

[jkcov]

Thanks for the replys guys iv had the engineer back today to range and like what d-hailsham said my boiler was over kw for the rads. Im now down to 13kw on the boiler and the gae usage over 2 mins went down by half. So will have to see how much of an impact that has on bills and heat of the house. We noticed that the hot water is using over 3 times the amount of gas than it should be tho and he tried to range rate that down but the d 22 option does not allow it in fact that option d22 states hot water demand is on 0 off and you cant change it. Anyone have any ideas how or if you can decrease the kw for the water? He has semi shut my stopcock to lower the incomming water flow as it was very fast and he thought that may help. Thanks again guys

 

[Bunnyman]

U cannont range rate the hot water and glad u didn't have a remeha as others have suggested the Vaillant is far superior in every way!

Untitled

• Bunnyman
• 26 Mar 2010
• 499

. Open the stop cock up full! An if u didn't want the extra flow rate y I'd he fit the 37kw? The 31 would have been better!

 

[D_Hailsham]

We noticed that the hot water is using over 3 times the amount of gas than it should be

What temperature have you set the HW to?

As the hot water is not being stored, there is no need to heat the water to 60°C. Just heat it to a usable temperature, say 40°C. You will then have no need to mix hot and cold to get a safe temperature.

 

[jkcov]

i have reduced the hw temp to 40c like you have suggested d_hailsham when we tested it was at 50c but looking at the boiler mans chart over the 2 mins we tested the hw with a bath tap on full it used 3 times the amount it should have. do i need vailent to look at this? obviously i have a boiler well over my need would i be better in the long run to selling this boiler and replacing it with a valient 824 or 831 and take the hit now rather than every year on my gas bill? would i notice much of a difference in gas consumption? now we have the kw for the ch set at 13kw it seems to be warming up ok not boiling hot but as i said the house temp never goes above 20/21c with this boiler but did with my flamingo we are still using 2 black units of gas over 3 hrs is that a lot? it seems a lot to me especially as last year my ave usage over this period was 5.7 units a day with the heating on 18c all day every day and 21c when i was in ie 6-10pm and wkends set at 21c at least 6 hrs. we tried to change the modulating time to 30mins but the rads went to cold.

 

[D_Hailsham]

When we tested it was at 50c, but looking at the boiler mans chart over the 2 mins we tested the hw with a bath tap on full it used 3 times the amount it should have.

Does your gas meter measure in cubic ft or cubic metres?

How many units of gas did you use over the two minute test.

now we have the kw for the ch set at 13kw it seems to be warming up ok not boiling hot but as i said the house temp never goes above 20/21c with this boiler but did with my flamingo

You should be able to get over 21C, particularly in this mild weather.

What are your flow and return temperatures?

Use the Boiler Size Calculator to find out the heating requirement of your house - deduct 2kW from the result as you have a combi boiler.

we are still using 2 black units of gas over 3 hrs is that a lot?

That depends on what the units are - see above.

we tried to change the modulating time to 30mins but the rads went to cold.

Don't understand what you mean by "modulating time".