60kw boiler

[VSR]

i currently have a hamworthy purewel 60kw boiler in working condition. recently some one suggested that i would be better off replacing it with a more effecient one. any one has any ideas about which model would do best instead and its cost? many thanks.
vsr

 

[Fluffster]

Need alot more info like do you live in a 20 bed stone block mansion or 20th floor 2 bed tower block.
60kw is what my old school used to run on so is pretty big for domestic purposes.

Pete

ps just saw your other post how many rads do you have and what size as if you need 60kw burner a chemical dosage on its own will have little effect on an old system.
What symptons do you have?

Pete

 

[Paul Barker]

Yes I agree I answered the other post without reading this one. A dose of chemicals won't renew a system of that nature. Expect to add to it a great deal of elbow grease. If your 60kw boilers cast iron heat exchanger is blcoked with hardened crusted magnetight there isn't a chemical made which will clear it. New heat exchanger or new boiler probably quite a lot of new bits to the system, and a really top market powerflush machine employed by highly skilled personel who offer you a guarantee.

If you want to solve your problems it will cost you a fortune.

If you want the same problems to keep haunting you, spend less than £600.

And in future avoid all system problems like pumping over, i.e. rectify system design faults. Fix all leaks. Install various filtering devices but not as a means of cleaning your system, as a means of protecting a cleaned system. Finally test your inhibitor anually.

 

[VSR]

dear fluffster and paulbarker,
many thanks.
it is a large house on four floors with around 35 radiators. how would the type of house effect the choice of boiler, would you please say? my existing boiler was only installed 5 years ago and had been serviced regularly. it is quite possible that sludge from elsewhere got into the boiler, but unlikley that the he itself is badly corroded - my guess.

VSR

 

[VSR]

sorry, the symptom is that several radiators remain cold.

 

[Fluffster]

35 rads over 4 floors is a commercial style system.
I take it you have zone controls on each floor/area?

Boiler choice is matched to required performance which needs a full survey of your house, however your controls are utmost important as I doubt you need all your rads on at the same time?
This is where it will save you money and undue wear on components.

Cast iron h/exchangers are very robust compared to modern aluminium and stainless steel but can also be less effecient.

You really need a RGI to come and survey the house to give you best specific advice.

Pete

 

[bengasman]

Very rarely is the cause of variation in radiator temperature found in the boiler.
As your house is zoned, or should be, with a 5 year old boiler, chances are the boiler was poorly installed, and not maintained by a good RGI.
You can have a poorly balanced system, or soiled/corroded.

 

[VSR]

unfortunately the system is not zoned. however, it would lend to have four zones, one of each floor. what would be the best way of zoning? a separate pump for each floor, with a multi channel control or a single pump (as it is now) with a motorised valve for each zone? the feed and return system comes off a service duct and (i think) it would be possible to run cables etc.

many thanks
VSR

 

[bengasman]

Not many houses this size in London, so am not an expert on it, but I would be hesitant to work with more than 1 pump.
I would look at 1 big pump, modulating, and close to the boiler.
Best to find a good installer to find and correct all current faults. That will be by far the most economical and reliable solution long term.
Do it wrong and you can be looking at a lot of cost and hassle over the years.
The saving on the gasbill alone will pay for a good engineer to do the job properly once and for all.

 

[BigBurner]

Points:

• The boiler is not old.
• There are system problems and probably with sludge in the system.

Do you want a new boiler because of greater economics in running?
What does the DHW?
A vented cylinder?
Do you have a U16 meter?

The system needs cleaning whether new boiler or not. Powerflushes are very expensive for what they are. First, X-800 should be run in the system - look at instructions and keep in as long as possible. Connecting the the system up to the cold mains and having only one rad on at a time can get rid of a lot of sludge. This is cheap to do and can be DIYed if you know how to connect up the mains to the system. After fit a Magnaclean filter to the boiler return pipe on the system and a gauze in-line filter adjacent.

If you want a new boiler (or need to because the old one is kaput), I would fit two[/b] 30kW boilers. Then you have backup if one is down. Look at the Broag 30C combi, which is a well priced quality boiler and they have a superb control system. http://www.avantaplus.co.uk It is well priced and the DHW section need not be connected. Or connect the DHW and have it as backup and isolated by a 1/4 turn valve, or connected just doing the showers only, to give high pressure from the mains. 60W of instant DHW may be all you need, and then you can get rid of the DHW cylinder if one there.

If going combi and no DHW cylinder, then use the Broag 39C combis. Which will give 32 litres/min if your cold mains can deliver that amount flow.

The Broags have integral weather compensation. I would have this connected up using the outside sensors and have both boilers set the same and connected to a low loss header. Off the header have the 4 CH zones with TRVs on each rad. One Grundfos Alpha smart pump will do and a zone valve for each CH zone. After the pump have a flow switch and this is the control interlock. When all TRVs are closed, the flow switch switches out the boilers. No stat on the floors, just 4 cheap simple timers.

If you have a DHW indirect cylinder heated by the boiler, have this off the low loss header. It is a case of the cylinder stat switch a relay. This switches a 28mm "diverter" valve, so all heat goes to the cylinder. The relay can switch out the CH pump, but need not to as it is a smart pump. The cylinder stat connection on the boilers each go to a set of contacts. This ramps the heat to to maximum of the boiler to give fast DHW reheat. When the cylinder is satisfied the diverter valve moves over to CH and the boilers revert back to weather compensation control, giving excellent condensing economy.

If using a cylinder, only in deepest winter will two boiler need to be switched on. The summer boiler can alternate each year to reduce and even out boiler wear.

 

[VSR]

dear bigburner,
you have been most helpful.

am i correct in thinking that i could do exactly as you suggested in terms of zoning/control (actually get a qualified person to do) while keeping the existing boiler ? the exisitng pump is a Grundfos UPE 40-80 F 250.

many thanks
VSR

 

[VSR]

Points:
[
Do you want a new boiler because of greater economics in running?
What does the DHW?
A vented cylinder?
Do you have a U16 meter?

yes i was thinking of economy of running, but am worries that the outlay will be large and payback time will be very long.
i am sorry that i do not know what any of 'DHW', 'Vented cylinder' or 'U16 meter' are

 

[BigBurner]

Points:
[
Do you want a new boiler because of greater economics in running?
What does the DHW?
A vented cylinder?
Do you have a U16 meter?

yes i was thinking of economy of running, but am worries that the outlay will be large and payback time will be very long.
i am sorry that i do not know what any of 'DHW', 'Vented cylinder' or 'U16 meter' are

A U16 meter is a large meter. Do you a large meter?
Do you have large and a small tank in the loft?
Do you heat you (Domestic Hot Water) DHW via the boiler using a cylinder?

Two 28C Broags are just under £1,300. Two 39C Broags are £1,600. That is with the integral weather compensation, which lowers and raises the radiator temperatures to the outside temp.
http://www.tradingdepot.co.uk/DEF/c.../Central Heating Boilers/Broag Remeha Boilers

The control options:
http://www.avantaplus.com/docs/Issue 5 -Avanta Schematics Booklet.pdf

 

[VSR]

many thanks again, bigburner

yes we do have a rather large gas meter. the boiler gives me hotwater as well and there are two tanks in the loft.

we bought the house recently and i am on a steep learning curve as far as these matters are concrned.

thanks again
vsr

 

[BigBurner]

dear bigburner,
you have been most helpful.

am i correct in thinking that i could do exactly as you suggested in terms of zoning/control (actually get a qualified person to do) while keeping the existing boiler ? the exisitng pump is a Grundfos UPE 40-80 F 250.

many thanks
VSR

The existing boiler will not have integral weather compensation. It can be added externally, but becomes more commercial then. I am trying to keep all domestic, so it is cheaper and easy for a domestic heating man to understand.

Depends on how the system is configured right now. Does it have two zone valves, one for CH and one for DHW? But, I would be inclined to do.......

The existing boiler can have a 3-way 28mm "diverter" valve [u[with an end switch[/u] on the boiler flow, switched via a cylinder stat. Grundfos Alpha smart pump between boiler and 3-way valve. A flow switch immediately after the pump wired into the room stat circuit of the boiler (switch out the burner only). Thermo rad valves on all rads. Have 4 zone valves one to each CH zone on the CH port of the 3-way valve. A cheap single channel timer controlling each zone, either on each floor or in a bank in a convenient place in the house. One timer for DHW too. No room stats, as the flow switch replaces that.

When running on CH: The 3-way valve is open to CH de-energised. If only one zone is switched on, or all zones, the boiler and pump run. If all TRVs close and no flow through the boiler, the smart pump backs off (modulates down) and burner is switch out via the flow switch. If the cylinder stat call for heat, 3-way valve is energises and sends all heat to the cylinder, by operating the pump and boiler burner. As there are no rad valve in the DHW circuit the pump winds up and switches in the flow switch and brings in the burner.

Have a tee before and after the flow switch and a 15mm in-line isolator between the level of the flow can be adjusted. before cut in and cut out.

You will then have a DHW priority system that sends all heat to the cylinder for a rapid re-heat, ensuring you rarely run out of DHW.