Heatslave 20/25 - Actuator rattling

[dalio66]

Hi, just wondering if anyone could help me.

I have a heatslave 20/25 oil fired boiler. Yesterday it started rattling. Closer inspection revealed that the sound is coming from the Actuator. At best it's a buzzing sound, at worst, it sounds like someone is firing an AK-47 off.

The sound is definitely coming from the actuator, as the housing is broken and you can see it. (see pic).

The system appears to have failed to central heating, although we also have hot water. My other half thinks that it's not as warm though. (I thought that systems fail to HW???)

Now, I'm confident enough to replace the actuator myself. Please can anyone confirm;

That this is likely to just require a new actuator, and not a complete diverter assembly?

The boiler and heatslave tank do not need draining prior to swapping the actuator?

That this is a simple, "pop off - pop on" job?


The system also loses pressure every few days, but this only appears to be when CH has been on, so I assume this is an issue at a radiator.


Many thanks in advance.

Untitled

• dalio66
• 20 Feb 2015
• 1

 

[underwurlde]

If the actuator is buzzing then it is at least trying to work. I'd purely guess that the thing the actuator is trying to move is frozen, i.e. the valve?

Can you remove the actuator and try to open / close the valve by hand? Bet it needs a bit of force...

A

 

[dalio66]

I haven't actually dismantled the appliance to get to the actuator yet. I'm trying to decide whether I need to replace just the actuator, the whole assembly or would be better with an engineer visit.

What you've said there makes sense. In which case, am I right in saying that replacing the actuator won't solve my problem, as its the actual valve that is sticking.. in which case I'd be better replacing the full assembly?

Strangely enough.... the clicking seems to have suddenly stopped and the boiler is running normally again! I guess this supports your theory further?!

Cheers.

 

[dalio66]

another update -

When the heating is turned on, the rattling stops.
Turn heating off = Rattling starts.
Run a hot tap = Rattling starts.

 

[oilhead]

Remove the actuator and you will be able to see whether the valve is stuck, quite common on this valve. If there is no discernible up and down movement of the valve, you will need a new cartridge, which is a drain down job. If you are lucky, there will be isolation valves so you only need to drain the boiler. With such a battered actuator, it would be wise to replace that also.

 

[underwurlde]

^ indeed.

When the heating is turned on, the rattling stops.
Turn heating off = Rattling starts.
Run a hot tap = Rattling starts.

Again, guessing here but it seems like the valve itself is stuck in the correct position for heating. When there is DHW demand, valve needs to move, can't because it is maybe stuck and hence the actuator starts straining (i.e. rattling).

Do you actually get hot water from the hot water tap?

Andy

 

[dalio66]

Thanks for the info. Yes we do have hot water, although it goes cold after a while. For example when we shower, by the end of the shower we have the heat turned right up and it's almost cold. We then have to wait for the water to heat up again.

 

[dalio66]

Can you confirm that these are the parts I need:

Worcester Bosch 87161051320 diverter valve cartridge (3 port)

Honeywell VC4613-30 actuator. (is there newer version of this?)

Many thanks.

 

[Boilerman2]

Those look correct -while you have boiler drained fill up the expansion vessel with compressed air to 1.0bar pressure, hopefully that will stabilise your water pressure loss problem although the flex hose connecting the vessel to the boiler may also be blocked

 

[underwurlde]

Bet you 5p that replacing just the valve will solve the problem of the rattling actuator & hopefully the rest of your problems. I take on board oilhead's suggestion of replacing the actuator too due to stressing: BUT if it is OK, why go to the expense of replacing it?

IF it is a stuck valve, question remains then as to WHY it became stuck? Take a good look at the old one if you decide to remove & replace it, as this could suggest pending future problems elsewhere maybe?

Andy

 

[oilhead]

The spring loaded cartridge on this valve is a common failure. It is also used on some stelrads, and a good stockist will direct you to this item rather than the Worcs unit. The seizure usually will be as a result of system contamination, and would probably benefit from a flush and fitting of a magnetic filter. This would also protect the pump and water jacket, to say nothing of the radiators and valves.

 

[dalio66]

Many thanks for assistance here - most helpful. Oilhead I have found an online firm selling this part for £30, or £50 at my local plumbase... seems reasonable.

Unfortunately I've found another issue today which I guess explains the pressure loss. This morning I charged the system back to 1.0bar before I went to work (as it dropped again to about .5)

Mrs has had the heating on all day and the system is currently showing 3 bar, However, The pressure relief pipe outside is dripping out water (it's at least filled the cup that I put there this morning!) I assume this is now a separate problem, or is this likely to rectify when replace the valve cartridge and drain/refill the system and recharge the expansion tank?

I've noticed that a valve underneath the expansion tank has been left in the open position by the engineer who serviced it last year... this is a cold pipe, should it not be closed? (the external refilling hose valve is closed)

Untitled

• dalio66
• 22 Feb 2015
• 1

 

[Boilerman2]

I did tell you what to do about the pressure problem in my last post!! EXPANSION VESSEL re-charge with air.

If you turn off the valve below the vessel in you latest pic you will introduce yet another fault as it is the fuel supply to the burner - don't knock your Service Engineer for leaving that one on!!!

 

[dalio66]

Yes I've just realised that now when I took the burner cover off! He's a good guy that engineer.. feel a bit silly now.

Well I'll give this all a bash on Tuesday when I'm off work. Something to look forward to.

Many thanks.

 

[underwurlde]

At least you know... the only stupid question is the one that does not get asked!

A