hi guys just a quicky ,i have a valliant system boiler and a y plan system and was just wondering do i balence the rads with the 3 port valve on the heating side or in the midle position ,at the mo the rads heat fine on the heating only but if i ask for water as well 2 of the downstairs rads lose heat and both trv and other valve is open
BALENCING QUESTION
- Thread starter LONDON
- Start date
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You need a balancing valve in the cylinder return as well. A gate valve is fine for this and is easier to set than otherwise far superior lever valves.
A few quid for the valve then however long it takes. Probably under an hour if access is good and there are no other problems/air locks.
Labour rates vary greatly, but between £50 and £90 an hour in London.
Labour rates vary greatly, but between £50 and £90 an hour in London.
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What sort of hw cylinder is it? If it is a modern fast recovery then I wouldn't put a balancing gate valve in the return as these need full flow to acheive their fast re-heat times.
In this case just re-balance your rads just on heating only.
If it is a standard cylinder then do as Dan says.
In this case just re-balance your rads just on heating only.
If it is a standard cylinder then do as Dan says.
I would suggest that you first try balancing your rads.
A simple start is to close all lockshields and then open each one one turn and the two problem rads two turns.
Finer adjustment if required see the FAQ on this site.
Tony
A simple start is to close all lockshields and then open each one one turn and the two problem rads two turns.
Finer adjustment if required see the FAQ on this site.
Tony
LONDON said:
Gate valves aren't much good for balancing, the resistance imposed isn't proportional to the opening; so almost all the flow regulation happens in the first turn from closed.
A needle valve is better.
http://www.hattersley.com/productView.asp?prodID=19&catID=3
A double-regulating valve is best of all, the advantage being that you can lock the setting so it can be isolated and re-opened without losing the balanced setting.
http://www.hattersley.com/productView.asp?prodID=55&catID=8
They cost more and I've never seen one on a domestic cylinder.
Other than mine.
For all he knows the problem might just be balancing of the existing rads!
Better to do that first and then fit the gate valve afterwards IF necessary.
Any reduction if flow to the HW will lengthen recovery of the cylinder!
Tony
Better to do that first and then fit the gate valve afterwards IF necessary.
Any reduction if flow to the HW will lengthen recovery of the cylinder!
Tony
I would never fit a balancing valve to a cylinder on a Y plan unless to acheive an optimum flowrate through the heat exchanger specified by the manufacturer.
If the two systems operate together whether they are S plan or Y plan then hot water should have priority IMO.
If the two systems operate together whether they are S plan or Y plan then hot water should have priority IMO.
It could be, but then he says it's fine on heating only, but that there's a loss of flow to 2 rads when on heating AND hot water.Agile said:
The cylinder is often near the boiler, it's piped in 22mm tube, and the cylinder coil is usually 22mm and has little hydraulic resistance. The result is a roaring short-circuit; most of the water goes through the cylinder coil and starves the heating circuit, which has a high hydraulioc resistance. In addition, the flow rate through the cylinder is excessive and the water returns to the boiler with a very low temperature loss, which reduces the boiler efficiency.
There's usually about 3kW or 5 kW allocated for the DHWS load. If he's losing heating whilst there's DHWS demand, it suggests the DHWS is getting 50% or more of the flow, which might be 8 or 10 kW.
Balenza said:
If you want hot water to have priority, then you'd go W-plan.
If you want to regulate the flow rate and have heating whilst there's a DHWS demand, you usually need a regulating valve.
http://content.honeywell.com/UK/homes/Catalogue/Sundial Plans/3.3 W Plan.pdf
To get the correct temperature drop one would assume.
Clearly the problem only arises when the midposition valve is supplying water to cylinder as well as radiators.
If the radiators are heating evenly, each one has the correct temperature difference between flow and return pipes, I would suggest installing a valve on the cylinder return pipe as it is causing the imbalance.
If the radiators are heating evenly, each one has the correct temperature difference between flow and return pipes, I would suggest installing a valve on the cylinder return pipe as it is causing the imbalance.
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