unvented system

[desrob]

punter has leaking cylinder,y plan,heated by oil boiler, he wants to change it for an unvented cylinder indirect ,he wants it in the attic and along to gable end about 5 and a bit meters any thoughts would be appreciated and a idea regarding the price range thankyou.

[gmac]

Main concerns i would have would be freezing in winter and having adequate pressure for the system, also be careful existing pipes and joints are upto increase in pressure if it an old system, also ensure you are able to get your discharge pipe out, but if positioned beside gable shouldn't be a problem. Personally i'd be looking to be in and out in a day, so a days labour plus materials, plus a wee mark up

[gmac]

don't forget your spark either

[AWheating]

its going to have to be altered to a s plan, the biggest changes apart from the move will be the discharge pipework and the alterations to cold supply. You will need to construct a heavy dutie tank stand and a walk way and loft light for yearly service and maintenece. Your sparks will have to rewire to s plan and also if needed move or add an immersion circuit. also everything will need lagging with 19mm-25mm lagging and whatever the cylinder manufacturers recommend for frost protection.

labour probably 2 days,sparks cost, over heads, profit, materials.

[unguided1]

Also you need to look at the loading for the roof joists if it is a large unvented cylinder, also you need to consider how your going to insulate the cylinder in the roof space

[gmac]

its going to have to be altered to a s plan, the biggest changes apart from the move will be the discharge pipework and the alterations to cold supply. You will need to construct a heavy dutie tank stand and a walk way and loft light for yearly service and maintenece. Your sparks will have to rewire to s plan and also if needed move or add an immersion circuit. also everything will need lagging with 19mm-25mm lagging and whatever the cylinder manufacturers recommend for frost protection.

labour probably 2 days,sparks cost, over heads, profit, materials.

It can be installed on a y plan saving alot of hassle and expense, the oso and rm models can be anyways.

[AWheating]

It can be installed on a y plan saving alot of hassle and expense, the oso and rm models can be anyways.

how do they get around not having a zone valve to comply with the requirements of g3?

[desrob]

Main concerns i would have would be freezing in winter and having adequate pressure for the system, also be careful existing pipes and joints are upto increase in pressure if it an old system, also ensure you are able to get your discharge pipe out, but if positioned beside gable shouldn't be a problem. Personally i'd be looking to be in and out in a day, so a days labour plus materials, plus a wee mark up

what do you mean regarding adequate pressure for system, this is a sealed system,your a fast worker in and out in a day,not me mate at least two full days,maybe even a third to commission.

[desrob]

how do they get around not having a zone valve to comply with the requirements of g3?

does the mid position not give enough control to comply , or do you have to zone each area were required.i do not fully understand what your saying can you please elaborate, thanks

[gmac]

how do they get around not having a zone valve to comply with the requirements of g3?

Here's a link to oso installation instructions, page 11 or 12. http://www.oso-ho****er.co.uk/uk/pdf...ion_manual.pdf
The savings could be the difference between getting the job and not getting the job and the spark might even say thankyou lol

[gmac]

what do you mean regarding adequate pressure for system, this is a sealed system,your a fast worker in and out in a day,not me mate at least two full days,maybe even a third to commission.

You're unvented is working off your mains supply, so if you have a low pressure mains supply, say 1bar, then it defeats the purpose of installing an unvented really, the better the mains supply to your cylinder, the better pressure out of your unvented, plus you'll be looking for a 22mm mains supply to your unvented,
When I say a day I'm looking at a nice smooth running job with no problems and my bitch boy bein on site, Without seeing the job it hard to give an accurate time scale, then again smooth running jobs are getting harder to come by.

[AWheating]

does the mid position not give enough control to comply , or do you have to zone each area were required.i do not fully understand what your saying can you please elaborate, thanks

yes the mid position cant be used for an unvented cylinder, you have to have a valve that is normally closed under fault/off conditions to protect from over heating the cylinder. if i remember with an unvented cylinder you require a min of 3 thermostatic controls, one of which must be a manual resetting lock out.