My mum and dad had no heating last week, but they did have hot water, so
I went to see if I could fix it. Their CH is a bit strange, I think.
They have no main room thermostat, but each radiator has a TRV (am I
right in thinking that at least one should not have a TRV?). It was
easy enough to discover that the zone valve for the heating wasn't
opening, so I took the head off and opened it by hand, assuming the
worst that could happen would be that now, the hot water would no longer
have priority over the CH. But thinking back, the spindle was very
stiff - I could only just open it by hand. Are they supposed to be so
stiff? I don't think I've encountered another one that was.

On 14/04/2016 10:02, Dan S. MacAbre wrote:
My mum and dad had no heating last week, but they did have hot water, so
I went to see if I could fix it. Their CH is a bit strange, I think.
They have no main room thermostat, but each radiator has a TRV (am I
right in thinking that at least one should not have a TRV?). It was
easy enough to discover that the zone valve for the heating wasn't
opening, so I took the head off and opened it by hand, assuming the
worst that could happen would be that now, the hot water would no longer
have priority over the CH. But thinking back, the spindle was very
stiff - I could only just open it by hand. Are they supposed to be so
stiff? I don't think I've encountered another one that was.

You haven't clicked the lever into the lock-out position by any chance?
http://inspectapedia.com/heat/Zone%20Valves012-DFs.jpg
You can manually use this lever to open the valve or lock it open
against the spring.

Normally the bathroom radiator/towel rail would be the ideal candidate
to leave without a TRV but if it's got one then simply leave it open.

www.GymRatZ.co.uk wrote:
On 14/04/2016 10:02, Dan S. MacAbre wrote:
My mum and dad had no heating last week, but they did have hot water, so
I went to see if I could fix it. Their CH is a bit strange, I think.
They have no main room thermostat, but each radiator has a TRV (am I
right in thinking that at least one should not have a TRV?). It was
easy enough to discover that the zone valve for the heating wasn't
opening, so I took the head off and opened it by hand, assuming the
worst that could happen would be that now, the hot water would no longer
have priority over the CH. But thinking back, the spindle was very
stiff - I could only just open it by hand. Are they supposed to be so
stiff? I don't think I've encountered another one that was.

You haven't clicked the lever into the lock-out position by any chance?
http://inspectapedia.com/heat/Zone%20Valves012-DFs.jpg
You can manually use this lever to open the valve or lock it open
against the spring.

It's under the upstairs floorboards, so not susceptible to accidental
tampering. Also, it was stuck in the closed position. My first thought
was to lock it open, but I couldn't move the lever in either direction.
As I couldn't get my head close enough to work out what I might be
doing wrong, I just took the head off, and opened it by turning the
shaft. But like I say, it was very stiff indeed.

Normally the bathroom radiator/towel rail would be the ideal candidate
to leave without a TRV but if it's got one then simply leave it open.

On 14/04/2016 10:02, Dan S. MacAbre wrote:
My mum and dad had no heating last week, but they did have hot water, so
I went to see if I could fix it. Their CH is a bit strange, I think.
They have no main room thermostat, but each radiator has a TRV (am I
right in thinking that at least one should not have a TRV?).

It depends on the system. Some boilers which need a bypass loop have
them fitted separately which means every radiator can have a TRV. See
http://wiki.diyfaq.org.uk/index.php?...room_radiators
- but NB most of that is beyond me



--
Robin
reply-to address is (intended to be) valid

On 14/04/2016 10:02, Dan S. MacAbre wrote:
My mum and dad had no heating last week, but they did have hot water, so
I went to see if I could fix it. Their CH is a bit strange, I think.
They have no main room thermostat, but each radiator has a TRV (am I
right in thinking that at least one should not have a TRV?). It was easy
enough to discover that the zone valve for the heating wasn't opening,
so I took the head off and opened it by hand, assuming the worst that
could happen would be that now, the hot water would no longer have
priority over the CH. But thinking back, the spindle was very stiff - I
could only just open it by hand. Are they supposed to be so stiff? I
don't think I've encountered another one that was.

No, they're not supposed to be stiff - you should be able to rotate the
shaft with your finger and thumb. That one has obviously seized, and
didn't open because the motor didn't have sufficient grunt to unstick it.

You could try to free it by rotating it back and forth a few times with
pair of pliers. If that doesn't work, it's new valve time.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Robin wrote:
On 14/04/2016 10:02, Dan S. MacAbre wrote:
My mum and dad had no heating last week, but they did have hot water, so
I went to see if I could fix it. Their CH is a bit strange, I think.
They have no main room thermostat, but each radiator has a TRV (am I
right in thinking that at least one should not have a TRV?).

It depends on the system. Some boilers which need a bypass loop have
them fitted separately which means every radiator can have a TRV. See
http://wiki.diyfaq.org.uk/index.php?...room_radiators
- but NB most of that is beyond me


I'll have to take a closer look at it, I think. One of the first things
I did in our house was to make a wiring diagram for the CH, and to try
and work out where all the pipes went. Wasn't much fun, though, and
I've not tried it for my mum and dad yet.

Roger Mills wrote:
On 14/04/2016 10:02, Dan S. MacAbre wrote:
My mum and dad had no heating last week, but they did have hot water, so
I went to see if I could fix it. Their CH is a bit strange, I think.
They have no main room thermostat, but each radiator has a TRV (am I
right in thinking that at least one should not have a TRV?). It was easy
enough to discover that the zone valve for the heating wasn't opening,
so I took the head off and opened it by hand, assuming the worst that
could happen would be that now, the hot water would no longer have
priority over the CH. But thinking back, the spindle was very stiff - I
could only just open it by hand. Are they supposed to be so stiff? I
don't think I've encountered another one that was.

No, they're not supposed to be stiff - you should be able to rotate the
shaft with your finger and thumb. That one has obviously seized, and
didn't open because the motor didn't have sufficient grunt to unstick it.

You could try to free it by rotating it back and forth a few times with
pair of pliers. If that doesn't work, it's new valve time.

That's what I was thinking. I'm not sure it's worth replacing, given
that there is no room thermostat. I might just leave them both opened.
OTOH, they use an immersion heater whenever they need hot water, which
isn't often, since they have a power shower and dishwasher. I guess
fitting a room thermostat would save a bit of money in the long term.

On 14/04/2016 11:36, Dan S. MacAbre wrote:
Roger Mills wrote:


You could try to free it by rotating it back and forth a few times with
pair of pliers. If that doesn't work, it's new valve time.

That's what I was thinking. I'm not sure it's worth replacing, given
that there is no room thermostat.

That may or may nor work, depending on how the system is configured.

If there are two separate zone valves - one for HW and one for heating -
that suggests that it's an S-Plan system. They normally work by using
the auxiliary contacts in the valve actuator to tell the boiler to fire
once the valve is fully open. I suppose that if the actuator is still in
circuit but not physically attached to the valve it will go through the
motions of opening valve, and turn the boiler on. The downside with
holding the valve open manually is that the radiators will get hot
whenever the boiler is heating the hot water, even if you don't want
them on.

I might just leave them both opened.
OTOH, they use an immersion heater whenever they need hot water, which
isn't often, since they have a power shower and dishwasher. I guess
fitting a room thermostat would save a bit of money in the long term.

Yes. the CH actuator should be switched by a room stat - and likewise
the HW actuator by a cylinder stat.

Then, the boiler will only fire when either or both are calling for heat.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Thu, 14 Apr 2016 11:36:51 +0100, Dan S. MacAbre wrote:

Roger Mills wrote:
On 14/04/2016 10:02, Dan S. MacAbre wrote:
snip.
OTOH, they use an immersion heater whenever they need hot water, which
isn't often, since they have a power shower and dishwasher. I guess
fitting a room thermostat would save a bit of money in the long term.

Not sure why they use an immersion for hot water if they have a boiler -
AFAIK it is cheaper to use the boiler to heat the water tank, and the
immersion is normally for emergencies.

With your particular problem, of course, the economics could change.

Cheers

Dave R

--
Windows 8.1 on PCSpecialist box

Roger Mills wrote:
On 14/04/2016 11:36, Dan S. MacAbre wrote:
Roger Mills wrote:


You could try to free it by rotating it back and forth a few times with
pair of pliers. If that doesn't work, it's new valve time.

That's what I was thinking. I'm not sure it's worth replacing, given
that there is no room thermostat.

That may or may nor work, depending on how the system is configured.

If there are two separate zone valves - one for HW and one for heating -
that suggests that it's an S-Plan system. They normally work by using
the auxiliary contacts in the valve actuator to tell the boiler to fire
once the valve is fully open. I suppose that if the actuator is still in
circuit but not physically attached to the valve it will go through the
motions of opening valve, and turn the boiler on. The downside with
holding the valve open manually is that the radiators will get hot
whenever the boiler is heating the hot water, even if you don't want
them on.

I might just leave them both opened.
OTOH, they use an immersion heater whenever they need hot water, which
isn't often, since they have a power shower and dishwasher. I guess
fitting a room thermostat would save a bit of money in the long term.

Yes. the CH actuator should be switched by a room stat - and likewise
the HW actuator by a cylinder stat.

Then, the boiler will only fire when either or both are calling for heat.

Okay, thanks. I'll familiarise myself with the S-plan wiring, and try
to work out if that's what they've got.

David wrote:
On Thu, 14 Apr 2016 11:36:51 +0100, Dan S. MacAbre wrote:

Roger Mills wrote:
On 14/04/2016 10:02, Dan S. MacAbre wrote:
snip.
OTOH, they use an immersion heater whenever they need hot water, which
isn't often, since they have a power shower and dishwasher. I guess
fitting a room thermostat would save a bit of money in the long term.

Not sure why they use an immersion for hot water if they have a boiler -
AFAIK it is cheaper to use the boiler to heat the water tank, and the
immersion is normally for emergencies.

Mum and dad aren't the most logical of people. Whenever I try to do
something to make their lives more efficient, they always fall back to
doing what they've always done.

With your particular problem, of course, the economics could change.

Cheers

Dave R