Thermal Store/Heat Bank or Two Combi's?

[Agile]

Dont expect any meaningful grants for solar!

If the Government wanted to reduce carbon emissions they would do better to grant for fitting condensing boilers to replace open flue appliances or better still to fit more loft insulation or cavity wall insulation.

Tony

 

[BigBurner]

BB, can you say how you combine DHW from two combis to run a bath?

JohnH74, has both connected for all the house and finds no problems.

The best way is to divide and rule. One combis doing upstairs one down stairs CH. Total independent zoning. One doing one bathroom one doing the other. One doing the kitchen tap, one doing the utility. If one is down you have backup. And one does not influence the other when taking showers.

You combine the two for the baths only. Use two check valves and a shock arrestor between the valves and the bath taps. Outlet from one combi with check valve, otulet from the other with check valve. A tee between with a small shock arrestor on this line.

As JohnH74 says, it fills the baths pronto.

Price up two decent combis to do the above and then a system boiler and cylinder with the zone valves etc. The two combis come out on top in costs and installation time. Two of them could be in the loft or side by side or on top of each other in a cupboard.

CH zoning, instant DHW forever (great for body jets), and no spec taken up by large cylinders. ....and redundancy built in. Always heat and DHW in the house. Wiring is super simple using a programmer timer. Having adjacent sockets for each combi mean just plug them and then using wireless programmers timers no wiring is done at all. So, simple.

Why many installers do not do this in two bathroom houses is beyond me, as they are cheap and offer so much more.

JohnH74, take no notice of the fool from Norwich.

 

[BigBurner]

I do not proclaim to be an expert (in fact I am a rank amatuer at best), but our current 2 combi's are joined together to provide all the DHW for the entire house.

They are T'd together just underneath the boilers and whenever a tap/shower/bath is turned on, both boilers fire up.

The plumber who fitted them did it this way as 1 boiler on its own (14l/min) couldnt cope with the water requirement from the taps.

I guess to run the showers on dedicated boilers and the taps on combined boilers would require separate dedicated plumbing to each shower and the rest of the DHW on a regular circuit. If this is the case, it sounds messy.

I am currently looking at a Torrent RE 277 Thermal Store (solar capability for future), with a 30-40kw standard boiler.
The Torrent would provide 25 l/min DHW.
The top part of the house would be on a sealed primary system (as no F&E tank above it) feeding direct of the boiler.
Downstairs on the house would run through the thermal store (F&E would sit on top of thermal store).
Until I get solar (when grants are available!), I will connect the boiler to the regular heating coil on the thermal store (this is half way up) and also to the solar coil (which is only 8kw and at the bottom).
Total c/h output required would be 30kw.
Water output required 25l/min+ for 2 en-suites+bath+jet shower/jacuzzi.

I am not interested in unvented system.
It is either the above or a couple of Baxi's again.

Thoughts?

JH

Consider a stainless pressurised heat bank, with only a solar coil and all else direct - a new system boiler can be used or the existing Ideal with water section disused. Have a flow and return to each CH circuit from the cylinder having a Smart pump on each and TRVs all around.

Look at these. stainless:
http://www.advanceappliances.co.uk/gas_or_oil_thermal_store_systems.html

They will add coils, temp probes for two boiler anti-cycle stats and make to bespoke to order.

See this thread:
//www.diynot.com/forums/viewtopic.php?t=137289

 

[gas4you]

Been busy googling again Dr Drivel

You certainly talk a good job, pity you have no practical experience of anything you are suggesting

OP, the most useful info that anyone on here can give you is the following.

WARNING

If you want to take the advice of someone who is incompetent, unqualified and has never fitted a boiler or unvented cylinder, or in fact anyting to do with heating in his life, then go ahead.

All his information is obtained from brochures and the internet, where in both mediums, manufacturers are always going to paint their products in a good light. Just search his previous, outrageous posts on here and then see for yourself. The only posters that appear to agree with him are those that are him using a different 'alias' and talking to himself

BB, you are still the laughing stock of this forum

 

[JohnH74]

This is funny...

BigBurner, Gas4You and DP certainly make a dull topic (to me anyway as I deal in cars) more fun to read about.

unfortunatly haven't got time to read all the posts to find out what the history is between each of you or find out which one to believe, as you all sound very believable.

My two combi's are currently twinned but every plumber (and I have had at least 6) that has been to look at the set up has pulled their face and are amazed it works. The area manager from Ideal was asked about it and he said they wouldnt cover that kind of set-up as combi's are not designed to work together. It however did work before it broke.

Whether it broke due to crap Ideal boilers or due to the design of the system, I do not know.

Replacing the combi's is my cheapest and easiest option, but if I get more reliability and performance from a Thermal Store (long term investment), then I would prefer that option.
Not many people have Thermal Stores though so I don't know if the performance will be better than 2 combi's for DHW.

JH

 

[BigBurner]

This is funny...

I have never met anyone from Norwich who is funny.

unfortunatly haven't got time to read all the posts to find out what the history is between each of you or find out which one to believe, as you all sound very believable.

I am the engineer he lifts floorboards.

My two combi's are currently twinned but every plumber (and I have had at least 6) that has been to look at the set up has pulled their face and are amazed it works. The area manager from Ideal was asked about it and he said they wouldnt cover that kind of set-up as combi's are not designed to work together. It however did work before it broke.

Whether it broke due to rubbish Ideal boilers or due to the design of the system, I do not know.

It broke because of rubbish Ideal boilers. Anyone with half an engineering brain can see two together will work. Water run through is well ..er, water running through. W-Bosch even sent me a diagram of how to couple up two of theirs. It is best to join the outlets for the high flows only - the baths - as I described.

Replacing the combi's is my cheapest and easiest option, but if I get more reliability and performance from a Thermal Store (long term investment), then I would prefer that option.
Not many people have Thermal Stores though so I don't know if the performance will be better than 2 combi's for DHW.
JH

Plenty of people have them. All major makers make them. The are taking off as energy prices rise, as they are superb for solar, heat pumps, wood burners, etc. The two stat anti-cycle feature really enhances a thermal store. The boiler only comes in for one long efficient burn. The boilers tend to last and last.

 

[gas4you]

About time you put up or shut up BB.

Why can't you openly admit to posters you have no training or gas qualifications that would make you competent to post answers?

You always avoid the truth, we are trained, qualified and competent, you just portray that image falsley.

As the OP states this is boring, but as long as you will not be honest with posters I will continue to inform them of your lack of hands on knowledge.

You can not tell any poster anything more than they can read in a brochure or google themselves, so how is this helping them

Come clean and admit that you only read about things. Your only engineering skills are those needed for turning the pages over in the brochures.

OP, I and all the other qualified and competent posters on here are traceable via our profiles, so anyone can check and confirm our validity.

Strange you can't do the same with the forum troll. What does that tell you

 

[DP]

Suggest the matter of coupling two combis for greater flow be discussed with makers. Have yet to have a maker agree that this is allowable.

Just because someone has two combis coupled, and he gets 'good' flowrate of hot water is akin to (today) seeing a new noncondensing 35kwatt boiler (fitted about three weeks ago) with inlet pressure of 12.5mbars.

Registered gas installers must do gas work as per the regs. Non registered can do what they like.

 

[Agile]

W-Bosch even sent me a diagram of how to couple up two of theirs.

Wow....

You mean that you could not even work it out for yourself?

Big Burner, if you are so confident about your capabilities then why is it that you will not join us for one of our meets with a nice dinner out?

 

[BigBurner]

W-Bosch even sent me a diagram of how to couple up two of theirs.

Wow....

You mean that you could not even work it out for yourself?

Big Burner, if you are so confident about your capabilities then why is it that you will not join us for one of our meets with a nice dinner out?

Sick to changing thermocouples. This is what you get what they take a 6 weeks CORGI course. They know all the answers.

 

[BigBurner]

W-Bosch even sent me a diagram of how to couple up two of theirs.

Wow....

You mean that you could not even work it out for yourself?

Big Burner, if you are so confident about your capabilities then why is it that you will not join us for one of our meets with a nice dinner out?

I wouldn't be seen dead with the likes of you. And I only go to class joints.

 

[BigBurner]

Suggest the matter of coupling two combis for greater flow be discussed with makers. Have yet to have a maker agree that this is allowable.

Just because someone has two combis coupled, and he gets 'good' flowrate of hot water is akin to (today) seeing a new noncondensing 35kwatt boiler (fitted about three weeks ago) with inlet pressure of 12.5mbars.

Registered gas installers must do gas work as per the regs. Non registered can do what they like.

If you know about heating, boilers and water systems, then anyone can see that coupling up two combis has no adverse affects. If in doubt pout a check valve on the inlet to each.

I have seen many coupled and they work superbly. Anyone who put a combi on 12.5 bar is an idiot and didn't even read the instructions.