Twin head pump or Y plan?

[Bunker]

Im quoting to replace a boiler (oil) and its currently got a twin head pump arrangement which seems to work ok. Shall I leave as is, or should I replace with Y plan (or even S plan I guess..).

 

[SimonG]

My preference is splan.

 

[leethegasman]

The twin head pumps are a good idea but they never Realy took off

 

[Roger Welton]

S plan every time

 

[Bunker]

Why is S plan the favourite? Also, I know you have to put a bypass on, but on Y plan you dont need one (although its still required) because you cannot close a 3 way valve..

 

[BLOD]

ive always found 2 port valves more reliable than 3 ports

 

[Roger Welton]

ive always found 2 port valves more reliable than 3 ports

Less to go wrong in them, no rectification circuit, and one less microswitch.

They are also less restrictive than 3 ports.

 

[solutions]

What happened to momo's hardley see them anymore allways spring return, im amazed boiler style diverter valves and motor heads have not come across in to seperate component systems like s and y plan.

 

[Ray Stafford]

ive always found 2 port valves more reliable than 3 ports

Just ran some stats, with interesting results.

Looking at our return-in-warranty stats, there is a clear difference in Honeywell valves between the 2 port and the 3 port.

The return rate on 2 port is 0.3%, or three in a thousand. The return rate for 3 port is 1.3%, or thirteen per thousand, or 4 times more failures - admittedly still a very small number.

With Drayton, both 2 port and 3 port have exactly the same failure rate - 0.8% or eight per thousand.

So the moral of the story is - if you are fitting 2 port valves, buy Honeywell, but for 3 port valves, go Drayton.

 

[Bunker]

Nice stats Ray

 

[AWheating]

Ray, is that return rate just the warranty period of the valve? If so what is the warranty length?

 

[Ray Stafford]

Ray, is that return rate just the warranty period of the valve? If so what is the warranty length?

Yes, its just the "in-warranty" which I believe is a year on both plus 6 months shelf life time (until we introduced our minimum 2 yr warranty but that was too recent to affect this).

In that respect it doesn't help to tell you if one manufacturer has a 5 year mean time before failure and the other has 25 years.

 

[solutions]

Yes, its just the "in-warranty" which I believe is a year on both plus 6 months shelf life time (until we introduced our minimum 2 yr warranty but that was too recent to affect this).

In that respect it doesn't help to tell you if one manufacturer has a 5 year mean time before failure and the other has 25 years.

Do you have any mean time before failure info for honeywell/ drayton valves or other brand stuff?

 

[Ray Stafford]

Do you have any mean time before failure info for honeywell/ drayton valves or other brand stuff?

Nope. The manufacturers would have it, but they would probably tell you their account details and PIN number before they would release that data.