Reading here of various problems with motorised valves from time to
time, I wonder if it might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Bob

In article ,
Graham. wrote:
On Fri, 01 Jun 2012 16:59:20 +0100, Bob Minchin
wrote:

Reading here of various problems with motorised valves from time to
time, I wonder if it might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Bob

I would just steer clear of 3 port mid-position valves, the 2 port
ones are reliable, and when they do fail it's the motor, and that's
easy and cheap to replace. The "wet" parts of my Honeywell Motorised
Valves are about 35 years old.

They do fail eventually. I had to replace one, fitted in 1988, a couple of
yeasr ago. The O-Ring failed resulting in a steady drip of water.

--
From KT24

Using a RISC OS computer running v5.18

On Fri, 01 Jun 2012 16:59:20 +0100, Bob Minchin
wrote:

Reading here of various problems with motorised valves from time to
time, I wonder if it might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Bob

I would just steer clear of 3 port mid-position valves, the 2 port
ones are reliable, and when they do fail it's the motor, and that's
easy and cheap to replace. The "wet" parts of my Honeywell Motorised
Valves are about 35 years old.

--
Graham.
%Profound_observation%

On Jun 1, 4:59*pm, Bob Minchin
wrote:
Reading here of various problems with motorised valves from time to
time, I wonder if it *might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Bob

Multiple pumps are no easier to balance than any other way of dividing
the output of a heating system.
In fact slightly worse, you can actually get flow reversal if one pump
is shut down whilst another is running

On 01/06/2012 18:35, harry wrote:
On Jun 1, 4:59 pm, Bob
wrote:
Reading here of various problems with motorised valves from time to
time, I wonder if it might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Bob

Multiple pumps are no easier to balance than any other way of dividing
the output of a heating system.
In fact slightly worse, you can actually get flow reversal if one pump
is shut down whilst another is running

I used two pumps with a 2 boiler installation. Simply add a non-return
valve for each pump.

In article , Bob Minchin
writes
Reading here of various problems with motorised valves from time to
time, I wonder if it might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Just thoughts but I think the risk of gravity or other spurious
circulation in the pump off loop(s) is too great, it doesn't take much
flow to get a rad to the just warm stage.
--
fred
it's a ba-na-na . . . .

On 1 Jun,
Graham. wrote:

On Fri, 01 Jun 2012 16:59:20 +0100, Bob Minchin
wrote:

Reading here of various problems with motorised valves from time to
time, I wonder if it might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Bob

I would just steer clear of 3 port mid-position valves, the 2 port
ones are reliable, and when they do fail it's the motor, and that's
easy and cheap to replace. The "wet" parts of my Honeywell Motorised
Valves are about 35 years old.

My current system originally had 3 port valves, changed* / repaired on
average every 6 months. Since modifying for 2 port valves I've only had one
change in near 20 years.


* Usually micro-switches. I kept a spare head and changed just the switches
after the first two failures.

--
B Thumbs
Change lycos to yahoo to reply

On 01/06/2012 16:59, Bob Minchin wrote:
Reading here of various problems with motorised valves from time to
time, I wonder if it might be better to install multiple pumps instead
when I re-do my heating system.

Any thoughts/experiences?

Bob

I wouldn't! If you have multiple zones with a single boiler, and one
pump per zone - which I think is what you're suggesting - you'll need
some logic to fire the boiler when one or more zones are calling for
heat. This is so easy with multiple 2-port valves and a single pump.
You'll also need to make sure that there's no unintended flow in zones
which are nor calling for heat. A non-running pump doesn't block the
flow in the way in which a closed zone valve does. Also, if your boiler
needs pump over-run with a by-pass circuit, I've no idea how to
implement that with multiple pumps!
--
Cheers,
Roger
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