Vaillant Turbomax Gas Guzzler....

[Christian and Beccy]

My Boiler is around 10 years old, it's a Vaillant Turbomax Pro 837e, it's not a condensing Boiler. It was bought with a focus on DHW performance and, regrettably, no real consideration was made towards running costs.

Today, 10 years later, I'm seeing monthly gas bills of £120-130/month over the Winter months, which I think is excessive. We cook entirely with Electric, the Gas is just for Heating and Hot Water.

The Bungalow isn't perfect, it could do with a bit more insulation, some of the Windows are now 10 years old (possibly need reglazing) and I do have a big Patio Door in the Kitchen (albeit very modern and with the highest efficiency glass I could buy), but even with those things in mind, I think it's still overly thirsty.

Furthermore, I don't think the performance is that great. Whether or not a problem has developed I don't know. I'm about to have a heating engineer out to look at it, once I can find one I feel that I can trust not to come and simply tell me I need to replace it.

I have the Hot Water control turned almost all the way up (58° on the display) and the Radiator dial also very high. Yet, the water seems to cycle between hot and luke warm. The heating also seems to struggle, it takes something like 2.5 hours to raise the temperature of the house from 19° to 21°, is this normal? It seems disproportionate with the amount of 'fuel' it's using.

Question is, is there much in the way of 'setup' and 'tuning' on these things? Could it simply be 'out of adjustment'? Or do they not work like that?

 

[Gasguru]

Check the diverter is working properly...they often stick meaning the radiators can heat up with a hot water demand and vice versa (causing short cycling and a slow warm up). If you've got pre-heat switched on that would make it worse.

Make sure the radiators are properly balanced...otherwise you will get increased gas usage too.

Also check the boiler has been range rated ie. the output is matched to the radiator load.

TRVs on most of the radiators and a correctly sited room thermostat (and correctly set corresponding rad) will also make a big difference.

Otherwise these boilers are generally fine and changing to a modern boiler will not save much on the gas bill. I'd prefer an old Turbomax Plus/Pro rather than a modern boiler.

 

[Christian and Beccy]

Gasguru - I appreciate your reply.

Regarding the diverter, I guess the heating engineer can check this? But does sound interesting.

Regarding radiator balance, again, has been done but probably room for improvement there.

I am interested in the range-rating comment. Is this a spec issue? or something that's adjustable? Again, is this something a good heating engineer can investigate? The bungalow has been extended since that boiler was fitted, if that's relevant.

I have 4kw of PV on the roof, so am interested in looking at having an Immersion Tank and possibly coming away from a Combi eventually if it proves to be viable, though yet to get some proper advice and that's really some way off.

 

[Agile]

Your gas bill is typical of an average consumption which is about £1400 pa for elect and gas. ( Before recent reductions are applied ).

Presumably you have never had the boiler serviced?

If its not serviced then the settings may be incorrect and the d0 in particular.

If it does not cycle on/off when heating from 19 C to 21 C then see what d0 reads and consider increasing it by about 2 or 3 kW.

Tony

 

[Gasguru]

Shouldn't be a problem to use the existing boiler to heat the cylinder too....it's just re-plumbed to provide separate zones for the cylinder and radiators off the existing radiator output.

 

[Tibbot]

You should make it clear to any person called that your expectation is to achieve a reduction in gas consumption. That way they have a chance to turn down the job. On an old system installed by others and possibly not maintained, I'd only offer an hourly rate for as long as it took to rectify (if possible) with no guarantee of success. That's as unlikely to be acceptable to most as it is to put right in a service visit.