Replacement Powerhead for Honeywell V4073A1039

Over the past week my central heating system has been playing up so at the weekend it was out with the multimeter to track down the problem. I came to the conclusion that I need to replace the powerhead on my diverter valve. As the powerhead on the V4073A1039 is easily replacable I thought great I'll just order a replacement powerhead and started trawling the web looking for the best prices. I quickly discovered that a replacement powerhead is actually more expensive than the complete valve/powerhead assembly .

So can anybody tell why this is the case. I am now working on the theory that I should just buy the compete assembly (powerhead and valve) and remove the new powerhead from the new valve and fit it to the old valve, or is there some vital piece of information I am missing that means this is not possible.

Any help is appreciated. Cheers.

I don't know where you've been looking, but a powerhead are cheaper than the whole valve.

However, you need to establish the general health of the system and whether or not the valve is moving freely. One common occurrence is that a sticking valve stresses the powerhead which then fails. In that situation, if you fit a new powerhead then that will also fail.

If you remove your old powerhead you can feel how easy it is to turn the valve spindle - it should be possible to do it by hand.

Goldberg, thanks for the reply. I have checked the spindle and it is moving quite freely. With regards to the pricing a couple of examples are:

UK Plumbing - V4073A1039 £56.93, 40003916-003 Replacement Powerhead for V4073A £60.69.
Heating Controls Online - V4073A1039 £49.40, 40003916-003 Replacement Powerhead for V4073A £55.32.

I have now checked out more sites and have found that most of them are selling the powerhead cheaper than the whole valve, it was just unfortunate that the first few I visted seem to have this strange pricing anomaly.

I wonder if Goldberg would be able to explain just how he thinks a seized shaft will "stress" the powerhead and make it fail?

Tony

Agile said:

I wonder if Goldberg would be able to explain just how he thinks a seized shaft will "stress" the powerhead and make it fail?

Click to expand...

Do you?

The thing I wonder about is your sanity, given that I haven't used the words "seized" and "shaft".

Goldberg said:

...One common occurrence is that a sticking valve stresses the powerhead which then fails. In that situation, if you fit a new powerhead then that will also fail...

Click to expand...

Would you be kind enough to use your great intellect and enormous experience to enlighten a simple rgi?

I have heard before that a sticking valve will cause a synchron motor to fail, but have never been able to figure out how the motor differentiates between a "stuck" valve, and a valve that has simply reached the end of the normal movement.
I have wondered about this for years.

To a simply mind like mine, it seems to be a matter of: end of movement = end of movement; what difference does it make?

Apologies if this sounds really dumb, but I am sure I am not the only one who doesn't quite understand this; nobody is perfect.

Many thanks in advance.