Worcester 15/19 Heatslave no HW or CH Water

[welshcob]

Hi, Guys,

I hope someone can help PLEASE, I have a Worcester 15/19 Heatslave with no HW or CH water, the other day I had a load noise coming from the water pump so I changed it, but now I have no HW or CH water, the pump is the correct way up & the electrics are correct, the diverter valve was changed about 18 months ago & since has run ok, today I isolated the boiler & drained it down, while empty I set the expansion vessel pressure to .5 bar & refilled it slowly via the filler loop, the diverter valve was set at manual & all bleed valves open, I restarted the boiler it will runs fine for about 6 or 7 mins then stop, it will not restart until it cools down, I removed the powerhead off the diverter valve, I checked the motor on it the reading is 2290 ohms’, I get a open & close circuit when the when I move the lever between manual & auto, I’m at my wits end as to what it can be, can someone HELP me PLEASE.


Living in Hope

Kelvin

 

[MeldrewsMate]

...I restarted the boiler it will runs fine for about 6 or 7 mins then stop, it will not restart until it cools down

Clearly the boiler works.
I assume the system pressure is above minimum, lets say 1 bar.
You have symptoms of low/zero water flow. Do you have pump isolating valves? Are they open?...No, I mean really open? Crappy 1/4 turn ball type isolators sometimes don't open (or close) properly and cause cavitation (noisy pump), or low flows.

Is the system water clean(ish)? Could the boiler pipework be blocked? Check the pipe temperatures at the flow and return connections to the boiler. If they're both hot after those 6 or 7 minutes then clearly the system isn't taking the heat away.

MM

 

[welshcob]

Hi MM,

Yep I set the boiler pressure at 1 bar on filling, just checked it & the pressure is just over 1 bar, both isolating valves have been changed due to leaking after replacing the pump, a new gate valve fitted on the bottom & a new ball valve fitted on the top of the pump (no room for gate valve due to pipe work) both valves are open, you say to "Check the pipe temperatures at the flow and return connections to the boiler" do you mean the HW or CH photo's below.

Thanks for your reply.

Kelvin

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• welshcob
• 29 Sep 2011
• 1

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[Burnerman]

When you ask for hot water, can you hear the flow switch click?
This should start the burner too (at least it does on my 12/14).
The 6 minute run is heating up the heatslave tank, I guess.
Is your new water pump actually spinning?
John

 

[welshcob]

Hi Burnerman,

Yes I can hear the flow switch click & yes the pump is spinning checked via centre nut, the oil boiler is 11 years old, there was some colouring in the CH water but no slug in the water, prior to changing the pump, the system performed very good, we only needed to set the dials at about a quarter to get good hot water, also the water in West Wales is very soft so I wouldn't expect to see any blockages.

To MM who replied earlier, can you tell me which pipes should be hot in the photo's I posted as not all the pipes where hot.

Thanks to all.

Kelvin

 

[Burnerman]

Have you bled at the 3 points on top of the boiler?
John

 

[spraggo]

I assume that you have released the air with a radiator key from the three bleed screws located at nine o`clock, six o`clock and three o`clock, looking at the photo showing the top of the boiler, while hot water and heating was switched off??.

 

[spraggo]

I assume that you have released the air with a radiator key from the three bleed screws located at nine o`clock, six o`clock and three o`clock, looking at the photo showing the top of the boiler, while hot water and heating was switched off??.

Sorry John you beat me to it

 

[welshcob]

Thanks Guys,

Yes all 3 bleed nipples where removed while I drained the boiler & where not replaced until the pipes/boiler was slowly refilled, also bleed after boiler was restarted, last year I fitted isolating valves (in the attic) to all 4 pipes (CH in/out & HW in/out) the boiler ran ok after the fitting of these valves.

If I can sort this out the winner gets a ride out in my Cobra.

Thanks again guys.

Kelvin

 

[spraggo]

Is the ex gauge reading 1.5 and does this fluctuate when heating is on?.

 

[Burnerman]

Try resetting the high limit thermostat, in case its deployed (underneath the control panel housing, left side I think).
John

 

[welshcob]

Hi spraggo & John,

I do appreciate your time that you are spending in replying to my problem.

Spraggo when you say "ex gauge reading 1.5" I assume you mean the boiler pressure gauge, if so when the boiler is 1st starts up from cold the it reads 1 bar in the short time the boiler runs this rises to about 1.3 bar & doesn't go any higher.

John the "the high limit thermostat" if I've got the right one you mention, it's at ground level & on the right, I'm not sure what this is for so I left well alone, it's presently set at approx 9.3.

Thanks again.

Kelvin

 

[spraggo]

It is obvious that there is a circulation problem. Either the pump or the pipework is airlocked or there is a valve not fully opened.

 

[Burnerman]

Hi Kelvin
The pressure in your boiler seems absolutely fine, so I'd forget about that one - 1 bar at rest rising to 1.3 is bang on.
The high limit thermostat reset is on the underneath of the electrical panel, with the thermostat knobs, left side. Its pressed up to reset.
I'm sorry, I don't know what you mean about something at ground level, 9.3 - unless its the burner air door screw. Could you post a pic, do you think?
At least its a mild evening!
John
PS Spraggo, I have to agree with you - just clutching at straws!
Kelvin knows what he's doing.
J.

 

[welshcob]

Hi John & Spraggo,

Yeah my boiler is getting to be a right pain.

John I've posted a photo of the control knob I mention earlier, I think it's something to do with the burner control.

Yes I have pressed the red reset button (top Left), after it's run it once (6 or 7mins) I have to wait most of the day before it will start up again (it will then start up without having to press the red reset button) which I believe that this is down to the boiler core being to hot, if I open the middle bleed valve I it's mostly steam coming out.

Today I intend to take off the powerhead & try to manually mover the diverter valve to see if it's stuck, t I can only try one job per day as everything gets so hot.

Thanks again

Kelvin

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• welshcob
• 30 Sep 2011
• 1