Worcester Heatslave 15/19 Problems

[Agile]

I don't have time to look up the boiler details.

But the operation of the pump needs to be checked, that should be heard starting when the boiler recognises a demand for hot water.

There might be a flow switch on the primary side to be activated when the pump starts. IF the pump is really running then that needs to be watched to see if it does move. If there is one and it moves then the switch needs to be checked to ensure that it is electrically making the circuit.

Tony

 

[Burnerman]

Ha Ha its your baby now John until Tony comes along

Haha grrrrreat
John

 

[Burnerman]

Just trying to think this one through.....
If the boiler is starting up from cold, it'll run for around 10 min until the heatslave tank is hot.....at this time, the water pump is running and it defaults to this, leaving the CH side alone. It should then fire up again, irrespective of what temperature the heatslave is at when the hot tap is opened, courtesy of the flow switch on the incoming cold feed. If CH is called for, the 3 port valve turns, water pump is running and the rads should heat.
So, the OP can have a tankful of hot water but nothing more - so I'd look carefully at the flow switch. I've never replaced one due to failure, only leakage.
At the same time, if the chrome screw is undone on the pump front (minimal leak) a small electrical screwdriver can be used to check if its spinning.
John

 

[Agile]

Easier to use a mechanical stethoscope to listen to the pump turning. ( Or just a screwdriver if you don't have the stethoscope )

Non invasive and you don't get wet.

 

[oilboffin]

Prob the diverted valve gooses but is it a vertical one with a thin spindle if so get pliers on spindle
and pull it up and down few time to shift limescale usually work for a bit then but need new cartridge or check actuator

 

[Terrywookfit]

If the divertor was "Goosed" the heat would be dissipating somewhere.

It sounds to me that the stat on the Heatslave tank is calling for heat and firing the burner until the boiler stat operates.
The heat is not transferring to the store. A faulty pump or an airlock would be my guess!

 

[pandr]

Thank you all for your replies and sorry I haven't responded for some time. We had to make a long drive to my parents-in-law so my pregnant, hormonal wife, who is having a sense of humour failure about the HT situation could have a shower!

Are you able to check for continuity across the flow switch terminals?

Unfortunately I don't have a multimeter and I'm also not sure which are the flow switch terminals, so I haven't been able to check.

But the operation of the pump needs to be checked, that should be heard starting when the boiler recognises a demand for hot water.

It does seems that the pump does not start when HW is called for.

There might be a flow switch on the primary side to be activated when the pump starts. IF the pump is really running then that needs to be watched to see if it does move. If there is one and it moves then the switch needs to be checked to ensure that it is electrically making the circuit.

At the same time, if the chrome screw is undone on the pump front (minimal leak) a small electrical screwdriver can be used to check if its spinning.

I don't have a mechanical stethoscope, but I undid the chrome screw on the pump front and with an electrical screwdriver and a torch, ascertained that the pump is not spinning with HW tap turned on (or otherwise), however it can be spun with the screwdriver so nothing is blocking it.

Prob the diverted valve gooses but is it a vertical one with a thin spindle if so get pliers on spindle
and pull it up and down few time to shift limescale usually work for a bit then but need new cartridge or check actuator

Is the diverted vale the pipe junction with a motor above it situated above the pump? It has a level on the side which can be moved up and then drops down, I've assume this should be diverting the water to the tank and HW tap, or the rads and have tried moving the lever with the tap on but nothing happens.

Very thankful for the suggestions and assistance. It's sounding more and more like I am going to have to wait until Tuesday and find a local expect who can come and take a look

 

[Burnerman]

You have identified the diverter valve correctly - just above the pump with an aluminium box on the top. So long as the burner is firing and the pump is running, hot water will either pass to the heatslave tank or the central heating circuit. You don't get both at the same time unless the valve has stuck in a middle position; hot water is the default when its called for. As you'll have gathered, it is a three port valve.
The diverter valve complete is quite an expensive item (over £100 for the genuine Honeywell unit) but the power head (alloy box) or indeed the motor within are available separately from the likes of Plumbcenter or Toolstation.
So, for one reason or another, initially it seems that the pump and burner aren't receiving their mains supply so that needs to be looked at.
Do let us know what the outcome is, and we hope all goes well with forthcoming events!
John

 

[pandr]

Do let us know what the outcome is, and we hope all goes well with forthcoming events!

Thanks for all your help. Despite everyone being busy after the bank holiday weekend I managed to get an engineer out today. It turns out that the circulating pump was the problem - it wasn't stuck and the capacitor was fine so in the end it had to be replaced In addition the diverter valve was stuck.

We are very pleased to have hot water after nearly 5 days and the household is queuing for the shower as I type!
Very appreciative the helpful community here.

 

[Burnerman]

Thanks for letting us know!
Maybe its a good move during the summer months just to run the heating from time to time, just to keep the diverter on the move. The water pump spins anyway, even if its just the heatslave tank being reheated.
I find you can get a bloomin' good shower from these boilers - in the summer when the incoming water temperature is warmish, my own 12/14 can run two showers at the same time.
Regards
John

 

[Terrywookfit]

The 12/14 and 15/19 both have a flow rate of 15 lpm.
The average 30kw gas combi is only about 11 lpm

 

[oilboffin]

Glad to know it's fixed

 

[oilboffin]

On the new worcesters (spelling)the diverter moves for 10sec if it hasn't been actuated for 24hours just to prevent sticking not a bad idea that