One for Drivel

[ChrisR]

Top floor Flat has U-duct so gas boiler replacement difficult.
2 beds, one shower.
Midday mains pressure about 1.2bar.
CWC on roof, 1000's of gallons, 2" feed.

Considering an electrically heated heatbank to replace old HWC, and supply CH, whose demand would only be about 8kW.

Probably better to use CWC, pumped or straight, than mains, as that might drop right off at peak times.

Pandoras, Pulsacoils, look a bit big, and/or expensive.
Could use 9kW electric boiler, but is there a heatbank out there?
It's near Heatweb, but they don't return calls.

 

[gas4you]

That'll give him something to google

 

[corgiman]

That'll give him something to google

he wont answer this because it s a reasoned and leveled arguement, he dont so that, he is just rude and ignorant

his mum probably didnt breast feed him. poor Lamb

 

[ChrisR]

bump

 

[Agile]

I think someone who did social work mentioned that there was a condensing boiler which was specified as being suitable for an SE duct.

Tony

 

[ChrisR]

Can't be true, because

A modern premix condensing boiler required the combustion air to be pure.

If there is a significant reduction of the 20.9 % of oxygen then the boiler will fail to work properly and could even become dangerous.

 

[Agile]

But that related to a premix boiler.

The one someone said was allowed to be connected to an SE duct was probably a Band B conventional burner which are far more tolerant as they pass excess air over the burner.

Tony

 

[mehran]

i was wondering... if a premix boiler have a lambda sensor like the vissemann 200-w has(well i think it does) could it be placed on a SE duct?

 

[ChrisR]

I would have thought so, but it might be sensitive to other poc's.
I wonder what they do with the condensation drain from a U duct - it could all end up in the bottom boiler!

Thermal stores have proved too difficult to get for this application. Expensive and on long lead times. An electric boiler's going in.

 

[Doctor Drivel]

Top floor Flat has U-duct so gas boiler replacement difficult.
2 beds, one shower.
Midday mains pressure about 1.2bar.
CWC on roof, 1000's of gallons, 2" feed.

Considering an electrically heated heatbank to replace old HWC, and supply CH, whose demand would only be about 8kW.

Probably better to use CWC, pumped or straight, than mains, as that might drop right off at peak times.

Pandoras, Pulsacoils, look a bit big, and/or expensive.
Could use 9kW electric boiler, but is there a heatbank out there?
It's near Heatweb, but they don't return calls.

Square thermal store/heat banks are around. DPS and Elson make them they take up far less space. Google Elson. If taken off the tank, then a whole house pump. Is the main pressure less at peak times? 1.2 is OK for shower and assume the flow is there. If a high rise the cold mains will most probably be pumped.

There are combis available that will fit onto a U duct. I would look into this route first. Contact the main British makers: Baxi/Pott, Ideal, Glow Worm, etc, as they have supplied these in the past to Local Authorities. They don't openly advertise U duct compatible, etc, as it is a specialist market, and they don't want DIYers and inexperienced plumbers playing around with U ducts compatible equipment. You may find it is a SE duct rather than a U duct as the air intake is usually at low level. Some have U duct jigs, etc, for their ranges. Forced flued boilers work well in U ducts. The old atmospheric burners were a pain the rear.

Some Pre-mix burners have had problems in U ducts when at the end of the duct as the air inside is heavy with products of combustion of other flats. If at the start of the duct then all is fine. If at the end of the duct get a rail burner, not pre-mix to be safe.

Condensing boilers may be exempt from SE/U duct applications. There again the makers will help.

 

[Doctor Drivel]

I would have thought so, but it might be sensitive to other poc's.
I wonder what they do with the condensation drain from a U duct - it could all end up in the bottom boiler!

SE and U ducts have always have had drains in them. If a water leak and it gets into the duct, it can fill up.

Thermal stores have proved too difficult to get for this application. Expensive and on long lead times. An electric boiler's going in.

Elson are usually quite quick in supplying.

 

[ChrisR]

Square thermal store/heat banks are around. DPS and Elson make them they take up far less space. Google Elson.

DPS too expensive and slow (2-3 weeks).
Elson don't make stores with CH facility afai can see.

There are combis available that will fit onto a U duct.

Not any more. Tried Baxi, WB and Corgi.
Not really happy to use a Combi on that supply though it could be pumped from the CWC.
A flued boiler could just about be fitted, in an awkward place, and with a long flue, going out through a tile-hung Mansard. Not appealing!

You may find it is a SE duct rather than a U duct as the air intake is usually at low level.

Normal U duct, intake on the roof. Edit - I typed SE instead of U.

 

[Doctor Drivel]

Square thermal store/heat banks are around. DPS and Elson make them they take up far less space. Google Elson.

DPS too expensive and slow (2-3 weeks).
Elson don't make stores with CH facility afai can see.

Gledhill ElectraMate? Give Elson a ring.

There are combis available that will fit onto a U duct.
Not any more. Tried Baxi, WB and Corgi.
[/quote]

I'm sure there is one or two and have seen the bumph but can't point to it. Ariston? They tend to have flues of long lengths and want into the LA market. I have seen blocks of flats fitted out in Aristons - not in U ducts.

If I recall, a forced flue boiler fluing into a SE or U duct just needs the flue inserting into the duct and nothing else jst good sealing. The normal modern boiler controls are good enough for the ducts. In the yea olden dayes, appliances into these ducts needed thermocouple devices, so special order gas fires were made with these on. The normal warm air units had just basic thermocouple devices.

Not really happy to use a Combi on that supply though it could be pumped from the CWC.

1.2 bar is fine, but the peak time pressure is what matters. Pumping it would be the best option if mains suspect. The Grundfos Booster? Also, pumps in the mains is just adding to the mains pump from the potable water tank in the block. It is not pumping the mains mains pipe. So, I don't see that being a problem. Then a Grundfos Booster can improve on the 1.2 bar.

Look again at installing a non-condensing rail burner combi. I'm sure one makers does it or approves of a standard boiler being fitted.

Tried Viallant? Lots of U ducts in Germany/Holland. Just did a Google and hey presto I was right...Vaillant have a se-duct adapter:
http://www.gasapplianceguide.co.uk/vaillant_flues_and_accessories.htm

Go Vaillant combi and pump it if your unsure of the mains supply - either the mains itself or from the tank.

 

[Doctor Drivel]

Square thermal store/heat banks are around. DPS and Elson make them they take up far less space. Google Elson.

DPS too expensive and slow (2-3 weeks).
Elson don't make stores with CH facility afai can see.

Gledhill ElectraMate? Give Elson a ring.

There are combis available that will fit onto a U duct.

Not any more. Tried Baxi, WB and Corgi.

I'm sure there is one or two and have seen the bumph but can't point to it. Ariston? They tend to have flues of long lengths and want into the LA market. I have seen blocks of flats fitted out in Aristons - not in U ducts.

If I recall, a forced flue boiler fluing into a SE or U duct just needs the flue inserting into the duct and nothing else jst good sealing. The normal modern boiler controls are good enough for the ducts. In the yea olden dayes, appliances into these ducts needed thermocouple devices, so special order gas fires were made with these on. The normal warm air units had just basic thermocouple devices.

Not really happy to use a Combi on that supply though it could be pumped from the CWC.

1.2 bar is fine, but the peak time pressure is what matters. Pumping it would be the best option if mains suspect. The Grundfos Booster? Also, pumps in the mains is just adding to the mains pump from the potable water tank in the block. It is not pumping the mains mains pipe. So, I don't see that being a problem. Then a Grundfos Booster can improve on the 1.2 bar.

Look again at installing a non-condensing rail burner combi. I'm sure one makers does it or approves of a standard boiler being fitted.

Tried Viallant? Lots of U ducts in Germany/Holland. Just did a Google and hey presto I was right...Vaillant have a se-duct adapter:
http://www.uk-plumbing.com/vaillant-seduct-flue-accessory-p-2420.html
£36.

Go Vaillant combi and pump it if you'r unsure of the mains supply - either the mains itself or from the tank.

The TurboMax is se-duct compatible:.
http://www.a1-gas.co.uk/html/heatprod/vaillant.html

 

[ChrisR]

It's

illegal

to

fit

a

noncondensing

boiler!

I know there were boilers which USED to be fittable to U ducts! They aren't any more!

Nothing post Turbomax compatible on the Vaillant website and it takes too long to call their technical line. 40 minute phone calls, I charge for!
Also I don't know what the pressure does at peak times. It would cost ££ to find out, and take time. Even a 7:30 am visit wouldn't PROVE much. Landlord is losing rent at about £60 per day, maybe more if he loses the tenant.
The old CF boiler started spilling for no apparent reason - hex is clean. Maybe the duct is faulty - don't want to install anything to it only to find that's the case.

It's a commercial world and a decision has to be made.
£500 for a 12kW Electric boiler which is being collected as I type, does the job, and is easy as pie to fit.