No hot water, CH ok Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Pivotal]

A few days ago we stopped getting hot water, I noted that the gauge on the boiler way low but not on the bottom so I added some more water into the system, but still no hot water. When I boost the HW or when it should be on, no activity at the boiler.

Ive checked that the CH work & thats fine, the boiler lights, I can hear the system moving water & the pipes warm up by the boiler & radiators.

The 3 way divertor by the bopiler was very warm even when the pipes were cold, I powered the system down & the heat disapated. It didnt come back on when I tried to boost the HW.

I found the manual override on the Diverter & after a short while the motor got hot.(I powered down the system & having taken off the cover saw the cam rotate away from the microswitches. I couldnt tell if the shaft was rotating anything.

Ive tried testing CH thermostat down, boiler sensor full & boosting, but to no avail, no noise from the boiler, pipes or anything, no ignition of the boiler.

I havent tested any voltages

Boiler - glow worm ultimate 44FF
Diverter - Honeywell (not clear model)

We live in an area where the build up of scale is evident but not excessive.

Any thoughts further test etc appreciated.

[SparkySi]

The programmer 'calls' for hot water by going through the cylinder stat. if the cylinder stat is closed (call for hot water) voltage is then sent to the mid position valve, which then tells the pump and boiler to work.

I would check the programmer is working ok, then the cylinder stat and lastly the mid position valve. If the central heating is working ok it proves the valve is telling the boiler to switch on.It can only really be the cylinder stat, programmer or valve.

I would look at the cylinder stat first (you'll probably have common, normally closed (call for hot water) and normally open (water satisfied) connections inside plus earth.

Hope it helps......

[Pivotal]

Here is what I have measured:

The tank stat has a normally open & normally closed microswitch that I can toggle manually. The current position is C & 1 closed.

The wiring from the stat & valve connect on a terminal block thus:

S. Stat wires
V. Valve wires

TB
1 S.Blue & V.Grey
2 S.Red
3 V.White
4 S.Yellow & V.Orange
5 nc
6 V.Blue
7 Earths

While I was there I did what tests I could for voltages.

System on HW & CH off
7 - 1 240v
6 - 1 240v
5 - 1 226v
3 - 1 235v
2 - 1 226v

System on HW on CH off
7 - 1 240v
6 - 1 240v
5 - 1 190v
3 - 1 240v
2 - 1 190v

System on HW off CH on
7 - 1 240v
6 - 1 240v
5 - 1 0V
3 - 1 0V
2 - 1 0V

On the other side of the terminal block are three cables.

Not sure what I should be doing now so grateful again for any further advice.

(The wife is sure when we first moved in we use to be able to heat the water whilst having the CH on, but certainly that was happening earlier this year.

Pete

[Pivotal]

Can someone tell me what I would have to do to remove & replace the diverter (assuming its faulty), will I have to drain the CH & HW systems? Would I be able to refill both (if needed) or does that require any special knowledge/tools)

Also above the valve just beyond the HW pipe is a screw, which if I turn slightly, water come out of at high pressure (this water has an odour so I'm assuming it has some treatment in it.) Is this used to release the pressure in the system?

[toneyt]

[quote="Pivotal"]Can someone tell me what I would have to do to remove & replace the diverter (assuming its faulty), will I have to drain the CH & HW systems? Would I be able to refill both (if needed) or does that require any special knowledge/tools)

Also above the valve just beyond the HW pipe is a screw, which if I turn slightly, water come out of at high pressure (this water has an odour so I'm assuming it has some treatment in it.) Is this used to release the pressure in the system?[/quote]

[toneyt]

if you have a honeywell actuator head you can try by replacing the synchron motor inside it failing that you need to see if it is a replaceable powerhead

[toneyt]

is the valve honeywell/acl?

[Pivotal]

The valve is a Honeywell 4073A.

I took the motor section off last night, when I turn the CH on it rotates approx 45 degrees, returns when the CH turned off with a hefty whack (either by switch or if I turn the spindle manually).

The spindle mounted on the valve body doesnt have the same range of movement, probably just half. When I rotate it there is a bang, the pipes shudder & the motor activates. all three pipes get hot.

[toneyt]

i would try to replace the whole powerhead,this only applies to honeywell valves that have a raised 'dimple' on the top of the cover of the motor,
if this is so you can (turn off power)
remove the head by undoing the 2 screws opposite to each other.
Beware though this has to have a dimple otherwise you will start a mini indoor water feature as the valve head without the raised dimple secures directly on to the body water seal and all!
when you have removed the valve head you may need to gently ease the arm to disengage to actuator spindle from the valve and remove.
depending on your electrical competence you can rewire the valve directly in to the wiring centre or cut it and use a 5 pin connector/junction box.
with the actuator off check the spindle moves freely,this only moves about 30 degrees in total,as the valve has a ball inside this leaves one port shut or both ports open but still only moves a small amount.
that said if the actuator head does not have a dimple then you are looking at replacing the complete valve (reccommended)
or if you are brave getting a new powerhead but also a neww conversion kit for the valve body which gives you the option of in the future replacing the head without draining down.if you want i could talk you through that but first establish if you have a DIMPLE !!!
the bang you get is the pump pressure as you open and shut the ports

[Pivotal]

Hmm, I removed the motor/mechanism from the body of the valve a couple of days ago, leaving a flat brass plate mounted by two screws on the valve body - is this the item you are referring too?

The spindle does only have about the 30 degree movement you spoke of, so imply its working but somewhere is blocked?

[toneyt]

i would be looking now to change the synchron otor of the valve about £10 or the complete actuator valve head known as a 'powerhead' about £40 the latter being the best as sometimes the motor does not always motor across to make the internal microswitches,this should make evertything work as normal,
you could also manuallymove the spindle to the hot water port B on the valve and feel the heated water from the boiler pass through to the cylinder this will give you some hot water in about 20 mins.
let me know how you get on
t

[Pivotal]

I will put the motor section back on tonight (need the CH,the wife is cold)


I tried the manual lever previously, but never got any hot water, the boiler doesnt fire up & I cannot hear any water being pumped.

[Pivotal]

Hi

I've put everything back together, no hot water when I move the manual lever, but then when manaually moved its doing the same thing as when the CH kicks in.

I honestly cannot see the logic in this valve if the motor moves the spindle, & the spindle moves in the valve, the only thing I can think logically is that the pipe that routes the flow around the HW tank must be blocked or the spindle has become disconnected from the internals, or failing that the amount of movement isnt enough to divert it from the CH to the HW (& I thought it diverted to HW by default).

[BlueFlame]

The v4073a is not energized when there is a HW demand. The valve is only energized for CH. When there is a DHW demand the sinal/voltage goes straight from the programmer to cylinder stat to boiler/pump. If the DHW is not working check cylinder stat and programmer are functioning correctly.

Harry

[BlueFlame]

Sparkisi has told you exactly how the system works. When there is only a DHW demand the motorised valve (v4073a) is not energised,. The programmer supplies a voltage through the cylinder stat to the motorised valve. Thus either you have a faulty cylinder thermostat, programmer or wiring problem between these items. Check there is voltage on the orange wire when there is only a demand for HW. if not check wires to and from cylinder stat. If no voltage to or after cylinder stat suspect the programmer to be faulty.

Harry