External combi oil boilers
- Thread starter early_911
- Start date
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If you have to have one of these inventions of the devil, then your best choice might be the HRM Wallstar combi. However limited your space, a combi will get you in the end, and probably in the pocket. There, I've told you, and you'll probably take no notice. The general point is DON'T HAVE A COMBI!!!!!
We fit the Grant outdoor modules, see www.grantuk.com. If we fit it you will get three years parts and labour warranty.
We disagree with the devil fearing 'oilman', whilst scale problems can be more of an issue with an oil combi than a gas one there is no rocket science inside these units.
The hot water flow rate of an oil combi is very good due to the better calorific value of the fuel. The heatstore in most oil combis gets round the slow start up.
Just don't try and run one if you haven't a high enough incoming water supply flow rate.
Simon
www.hwch.co.uk
We disagree with the devil fearing 'oilman', whilst scale problems can be more of an issue with an oil combi than a gas one there is no rocket science inside these units.
The hot water flow rate of an oil combi is very good due to the better calorific value of the fuel. The heatstore in most oil combis gets round the slow start up.
Just don't try and run one if you haven't a high enough incoming water supply flow rate.
Simon
www.hwch.co.uk
simond said:
You will no doubt ensure overall your costs for possible repair work are included in the installation charges. To do otherwise would ensure you will go out of business in the long term.
Who was claiming rocket science? Fact is, with the boilers and systems I attend, the ones which have a higher cost of ownership are combi boilers, of all makes.
This is nonsense. A 28kW boiler is a 28kW boiler regardless of the type of fuel used. The heat store also contributes to increased fuel costs as the boiler stays hot 24 hours a day just so you don't have a slow start up.
In the end, the hot water supply flows through a 15mm pipe. So if one person is having a shower and someone else turns a hot tap on, the person in the shower may well notice it.
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Yes, you are right about my calorific value comment. I edited my text before posting and it ended up with a mixed message, sorry about that.
What I was intending to say was that a direct hot water fed oil fired boiler in a domestic environment can be larger in output due to the type of fuel used. Thus most oil combis can deliver 20l/m in their sleep whereas in the gas arena only the Bosch Hiflow 440 can do it.
The warranty we give our customers is part of the close relationship we have with the manufacturer. I am not aware of Grant being about to go bust.
With over 6m combination units (gas and oil) in the UK it is reasonable to suggest they have been a success.
In Germany a combi is virtually identical to a system boiler. A German system boiler uses the combi diverter valve to apportion CH and HW Cylinder primaries. The only difference in most German market boilers (eg: Vaillant, German Bosch (larger CDi) and Viessmann) between combi and the system boiler variant is the addition of a hot water heat exchanger - everything else is identical.
NB: Out of these only Viessmann think the UK plumbers are ready and sell 'German' spec boilers in the UK. Vaillant UK don't offer the internal valve (using a UK market external interface called VR65) and Bosch sell an adaptor kit for an internal diverter. The latter two must think we heating engineers aren't yet ready for such a change.
The result of the Germans rationalisation and simplification is commonality of parts across the piece, lower production costs, easier chance of 1st fix repairs, one set of training.
Whether you like combis or not, the technology is here to stay and more and more 'standard' boilers will be a combi with one part missing.
We regularly come across old Vaillant VCW combis which have given 20 yrs sterling service.
Those fearing the devil had better book a course now.
Regards
Simon
www.hwch.co.uk
Yes, you are right about my calorific value comment. I edited my text before posting and it ended up with a mixed message, sorry about that.
What I was intending to say was that a direct hot water fed oil fired boiler in a domestic environment can be larger in output due to the type of fuel used. Thus most oil combis can deliver 20l/m in their sleep whereas in the gas arena only the Bosch Hiflow 440 can do it.
The warranty we give our customers is part of the close relationship we have with the manufacturer. I am not aware of Grant being about to go bust.
With over 6m combination units (gas and oil) in the UK it is reasonable to suggest they have been a success.
In Germany a combi is virtually identical to a system boiler. A German system boiler uses the combi diverter valve to apportion CH and HW Cylinder primaries. The only difference in most German market boilers (eg: Vaillant, German Bosch (larger CDi) and Viessmann) between combi and the system boiler variant is the addition of a hot water heat exchanger - everything else is identical.
NB: Out of these only Viessmann think the UK plumbers are ready and sell 'German' spec boilers in the UK. Vaillant UK don't offer the internal valve (using a UK market external interface called VR65) and Bosch sell an adaptor kit for an internal diverter. The latter two must think we heating engineers aren't yet ready for such a change.
The result of the Germans rationalisation and simplification is commonality of parts across the piece, lower production costs, easier chance of 1st fix repairs, one set of training.
Whether you like combis or not, the technology is here to stay and more and more 'standard' boilers will be a combi with one part missing.
We regularly come across old Vaillant VCW combis which have given 20 yrs sterling service.
Those fearing the devil had better book a course now.
Regards
Simon
www.hwch.co.uk
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