Hi,

HW has been working all summer, but attempting to re-start CH lead to
blown fuse (on timer/control/punp/valve circuit) - not sure if this was
coincidence or not. Now the HW does not work - boiler won't start
(pilot on and running) - no CH either.

After replacing the fuse, I confirmed that the pump is running, by
powering it directly. I also suspected the two-port valve (stuck shut?)
and tried the manual open switch, but can't budge this past the central
position (so I'm not sure if the valve is open or closed). Boiler won't
start in any case.

The system is 20+ years old, and the coil in the HW tank appears to
have a hole, as I am getting water through the overflow (even though
the boiler isn't on...), and is probably full of scale by now. So, I
will replace the cylinder and the valve, but would like to be sure
there isn't a further problem here that will stop the system working
when it is back together (especially as the valve is so conveniently
placed behind the cylinder, making future access very difficult).

Any suggestions what else I can try to confirm that a dead valve is
really the problem?

Alternatively, am I barking up the wrong tree completely, and if I am,
what else do you recommend I check?

Thanks/Paul

expressed precisely :
After replacing the fuse, I confirmed that the pump is running, by
powering it directly. I also suspected the two-port valve (stuck shut?)
and tried the manual open switch, but can't budge this past the central
position (so I'm not sure if the valve is open or closed). Boiler won't
start in any case.

The just might have failed due to old age.

Did it blow again?

Any suggestions what else I can try to confirm that a dead valve is
really the problem?

Remove the actuator (the head part of the valve) and see if that
operates by itself as you select HW, HW + CH, then CH alone. Then check
that you can turn the valve itself with a just a little more than bare
finger pressure on the half moon shaped shaft top of the valve.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.org

In an earlier contribution to this discussion,
wrote:

Hi,

HW has been working all summer, but attempting to re-start CH lead to
blown fuse (on timer/control/punp/valve circuit) - not sure if this
was coincidence or not. Now the HW does not work - boiler won't start
(pilot on and running) - no CH either.

After replacing the fuse, I confirmed that the pump is running, by
powering it directly. I also suspected the two-port valve (stuck
shut?) and tried the manual open switch, but can't budge this past
the central position (so I'm not sure if the valve is open or
closed). Boiler won't start in any case.

The system is 20+ years old, and the coil in the HW tank appears to
have a hole, as I am getting water through the overflow (even though
the boiler isn't on...), and is probably full of scale by now. So, I
will replace the cylinder and the valve, but would like to be sure
there isn't a further problem here that will stop the system working
when it is back together (especially as the valve is so conveniently
placed behind the cylinder, making future access very difficult).

Any suggestions what else I can try to confirm that a dead valve is
really the problem?

Alternatively, am I barking up the wrong tree completely, and if I am,
what else do you recommend I check?

Thanks/Paul

I'm not entirely sure from your description what sort of system you have.
You mention a 2-port valve - which suggests that you might have a C-Plan
system (see http://content.honeywell.com/uk/homes/systems.htm) with gravity
hot water and pumped heating. Is that what you have?

Or is it perhaps a Y-Plan (or even W-Plan) fully pumped system with a 3-port
(one inlet and 2 outlets) valve rather than a 2-port valve?

Once we've established this, we can tell you what to look for.

Is it the small fill & expansion tank which is overflowing, and is the level
in this *lower* than that in the main cold water heated tank for the hot
water system? If so, it's possible that the indirect coil inside the hot
cylinder is leaking - assuming you've eliminated the ball valve on the F&E
tank as the culprit.
--
Cheers,
Set Square
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In an earlier contribution to this discussion,
Set Square wrote:

Correction

Is it the small fill & expansion tank which is overflowing, and is
the level in this *lower* than that in the main cold water HEADER
tank for the hot water system? If so, it's possible that the indirect
coil inside the hot cylinder is leaking - assuming you've eliminated
the ball valve on the F&E tank as the culprit.

[Don't ask me why I typed "heated"]

--
Cheers,
Set Square
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Hi,

After a delay, here are some answers to the above questions:

1) The system is type "S" - 2 x 2-port valves - the second valve was
under the floorboards.
2) The expansion tank level is lower than the main cold water tank. I
have also confirmed that the float/ball valve are regulating water
level correctly.

Replacement of the H/W valve restored operation of the H/W side of the
system. Setting the C/H valve to "manual on" causes the rads to
warm-up. The valve does not appear to work (tried sperate mains
connection - nothing happens). I am trying to fit a replacement
powerhead (Honeywell 4043), but the "drive shaft" to the valve seems to
totate between 10 and 12 o'clock, whereas the powerhead moves from 11
to 1 o'clock (the old one does the same), so although the new powerhead
works, the range of rotation it has does not open the valve.

Does this mean the valve itself is faulty/needs replacing?

Regarding the overflow siutuation , the overflow outlet (in the
expansion tank) is the same level as the water level in the tank, so
water starts to flow when the heating/water is on. Is this standard? I
would have expected some "headroom" between the resting water level and
the level of the overflow outlet?

Thanks/Paul


Set Square wrote:
Is it the small fill & expansion tank which is overflowing, and is
the level in this *lower* than that in the main cold water HEADER
tank for the hot water system? If so, it's possible that the indirect
coil inside the hot cylinder is leaking - assuming you've eliminated
the ball valve on the F&E tank as the culprit.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

In an earlier contribution to this discussion,
wrote:

Hi,

After a delay, here are some answers to the above questions:

1) The system is type "S" - 2 x 2-port valves - the second valve was
under the floorboards.
2) The expansion tank level is lower than the main cold water tank. I
have also confirmed that the float/ball valve are regulating water
level correctly.

Replacement of the H/W valve restored operation of the H/W side of the
system. Setting the C/H valve to "manual on" causes the rads to
warm-up. The valve does not appear to work (tried sperate mains
connection - nothing happens). I am trying to fit a replacement
powerhead (Honeywell 4043), but the "drive shaft" to the valve seems
to totate between 10 and 12 o'clock, whereas the powerhead moves from
11 to 1 o'clock (the old one does the same), so although the new
powerhead works, the range of rotation it has does not open the valve.

Does this mean the valve itself is faulty/needs replacing?

It sounds as if either the wet part of the valve is partially seized - and
not moving through its full travel - or else the power head is not
compatible with the valve. Is it the same type as the HW valve? If so, what
range of travel does that - and its actuator - have?

Regarding the overflow siutuation , the overflow outlet (in the
expansion tank) is the same level as the water level in the tank, so
water starts to flow when the heating/water is on. Is this standard? I
would have expected some "headroom" between the resting water level
and the level of the overflow outlet?

The F&E tank should only contain 2 or 3 inches of water when the system is
cold - just enough to make sure that the pipe in the bottom, which feeds the
system, is adequately covered. The level needs to be able to rise quite a
long way without overflowing when the system gets hot and the circulating
water expands. Remove some of the water, and bend the arm of the ballvalve
so that it shuts off at a lower level.
--
Cheers,
Set Square
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