S Plan or Y Plan

Hi,

What are the pro's and con's of S Plan vs Y Plan heating arrangements? I am getting a new heating system and I don't know which one to go for.

TIA, W

Reply to
W
Loading thread data ...

Y-Plan = cheaper, often more compact. S-Plan = easier to understand and wire up, more reliable, ability to expand to multiple zones. Zone valves can be placed in separate locations, if desirable.

My system has 4 zones currently, which may expand to 6. The zone valves for them are:

Kitchen -> under kitchen cupboards next to kickspace fan convector. Downstairs -> under stairs cupboard Upstairs -> under stairs cupboard Hot water -> in loft on cylinder

Potential expansion: Conservatory -> under kitchen cupboard, or in conservatory itself Loft Conversion -> in loft next to boiler.

If you're having a new system installed from scratch, it is well worth subzoning now, whilst it will be cheap to do so. Having separate timing and temperature settings for upstairs/downstairs is very useful. There's no need to heat the bedrooms during the day.

If you have a conservatory, independent timing is also very useful and could save a fortune in heating bills. I'm toying with the idea of installing a motion detector in series with the programmable thermostat in there. Just walk in and the room is toasty 5 minutes later (I will be installing a grossly oversized fan convector as the rapid warmup should give good energy efficiency by encouraging us not to heat it when not required).

Christian.

Reply to
Christian McArdle

A Y-plan uses less components - one motorised valve rather than two (or more) and probably doesn't need a bi-pass valve. However, the 3-port mid-position valve plays a strategic role in the overall control of the boiler and pump, and is not very reliable - causing the whole system to fail when it goes wrong.

An S-plan is a better technical solution, and gives greater flexibility - since extra zones can easily be added (called S-plan-plus) if the pipework layout permits. With a Y-plan, you're stuck with a single heating zone.

Reply to
Set Square

The Y plan 3 port valve is cheaper to initially buy than two zone valves and there is less pipework involved in connecting it. I had Y plan on my old system and the main item that regularly failed was the 3 port valve motor - so my new system uses S plan zone valves which are likely to be more reliable as they are either open or closed rather than 3 position. Another advantage of S plan is diagnosing any faults should be easier - it is easy to determine if the valves are operating correctly compared to the Y plan 3 port types.

When selecting valves to use - there are many makes to choose from, some better than others for similar prices. I chose the Honeywell V4043H as it appeared to be well made and has a good reputation (my plumbers merchant agreed with my choice also).

Dave

Reply to
logized

Others have mentioned just about the whole range of reasons. I'll add that with S-plan you have some back up when things go wrong. You can manually open the failed valve and run the other 'zone'.

Another things to remember is that if you have a HW cylinder an immersion is a small cost which can save a great deal of hassle if the boiler stops.

Reply to
Ed Sirett

Thanks to all for the help.

W.

Reply to
W

s plan is the best...........honeywell valves..

-- gastec

Reply to
gastec

Agreed. Honeywell or Horstmann valves. (The latter being electrically Class II don't require an earth wire which makes for less of bundle earths trying to get into a terminal in the wiring centre). They are also interchangable with the Honeywell plumbing part. They also operate the micro switch when in manual mode (can be useful).

Don't use Danfoss.

S-plan gives an easy upgrade path for extra zones at a latter date (e.g. extension or diving into zones)l.

Reply to
Ed Sirett

S-Plan every time. Y-Plan is a dinosaur.

S-Plan is fundamentally more extensible (can handle more than 2 zones), easier to understand and more compatible with modern equipment. Only disadvantages are very slightly greater cost for a 2 zone system and need for slightly more room for the extra valve.

Christian.

Reply to
Christian McArdle

I am in total agreement that S-Plan is preferable.

Y-Plan does have *some* advantages - such that a single 3-port valve is cheaper than two 2-port valves, and a 3-port valve always provides at least one flow path, so you're less likely to need a by-pass circuit.

Y-Plan has the disadvantage, as mentioned by Christian, that it can't readily be extended into additional zones. The fundamental disadvantage in my view is that the motor drive is all mixed with boiler and pump switching in quite a complex way, such that the valve actuator has a more strategic role than its S-Plan counterparts. It is a single point of failure for the whole system - as witnessed by the large number of posts here about 3-port valve woes.

Reply to
Set Square

Due to a shortage at the time of 3 port valves at my supplier I utilised two

3 port ones in a modified sort of Y plan. It was much more complex to wire up, requiring 3 wires to various timers and thermostats rather than two, and proved unreliable, with frequent problems with microswitches in the valves. I have since converted to 2 port valves with S+ plan, with a huge increase in reliability.
Reply to
<me9

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.