More interesting valve facts from Sunvic correspondence: Reads from the bottom (Still not entirely sure that I understand all this without having specimens to play with though!)
Sunvic latest reply:
I sent the PDF of the spring return valve as the internals are the same as for the MoMo. I don?t have a PDF for the MoMo valve. The only difference is, in the MoMo valve there is only one shoe, where there are two in the spring return valve.
The MoMo actuator always moves in the one direction in increments of 90° turns. The spring return moves in one direction in increments of 45° turns, but always comes back the way it went.
The MoMo actuator will fit and operate on a spring return valve, but a spring return actuator, although it will fit a MoMo valve, will not operate because there is only one shoe in the valve.
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Sent: 03 September 2010 18:25 To: Sunvic HelpDesk Subject: Re: SDMV2304 3 port momo valve actuator.
Thanks for the additional info.
But you have provided a pdf for a spring return valve, which creates more confusion.
I had assumed that you said the momo actuator would not suit a ball type valve because the momo spindle needed a complete rotation. Separately, I have been told that the momo actuator only rotates in one direction, which would appear to back up what I had assumed: that the momo must rotate a third of a turn in the same direction with each activation. Thus I would need to buy the complete valve and actuator.
Now you have sent me your picture of the valve, which looks like it would revolve completely, but indicated that it works with a spring return, so may not rotate completely after all!?
Still has me scratching my head: but your valves do indeed look cleverer inside than the other makes I have seen so far, so I'll probably be buying a complete unit anyway, but I'd be interested in clearing up these points before I do.
Cheers,
rom: Sunvic HelpDesk
Sent: Friday, September 03, 2010 9:22 AM Subject: RE: SDMV2304 3 port momo valve actuator.
Our valves have either one shoe or two shoes (depending on the type of valve) which rotates to cover the port which is not calling for heat at that time. Please refer to the bottom page of the attached file which shows a sectioned view of one of our valves.
The cam that drives our valve spindles round, is located dead centre of the mounting plate. I believe on a Honeywell actuator, it?s offset.
Sent: 02 September 2010 16:36 To: Sunvic HelpDesk Subject: Re: SDMV2304 3 port momo valve actuator.
Thanks for the reply.
You have me puzzled though. The current actuator is a Honeywell, but I don't think the valve was the same make. It does have a ball at the water diverting end though - which is what I thought most of these valves had. I was thinking any differences might be in the mounting plate screw holes and/or spindle pattern, and had not thought the internals of the valve would make a difference.
Can you explain what exactly would be the problem with trying to fit to a ball type valve please?
Thank you,
From: Sunvic HelpDesk
Sent: Thursday, September 02, 2010 7:58 AM Subject: RE: SDMV2304 3 port momo valve actuator.
Thank you for your enquiry regarding the MoMo actuator. When looking for the actuator without the valve, you need to quote the number SDM 1901. We deal with companies such as Plumb center, C.E.F. Stearn electrical, Edmundsons etc.
The actuator will fit your existing valve (as long as it?s not a Honeywell type with a ball) and has the same wire colours, less an Earth wire, as our actuator is double insulated.
No new programmer required.
Subject: SDMV2304 3 port momo valve actuator.
Dear Sunvic,
I have, over the last few years, had to replace the actuator on our 3 port valve three times, due to the failure of the microswitches in conventional designs.
I only recently heard of your 'momo' type valves, and it seems that these might be what I have been looking for, and the SDMV2304, would appear to be equivalent to what we have.
However, I have not come across a site that sells the momo actuator alone, so I am wondering if you can tell me if the actuators are available separately and if they fit the conventional valve plate and spindle of existing valves? Obviously I would prefer not to have to interfere unnecessarily with the pipework - especially as this one is in a very tight cupboard space.
Also, would the momo type actuator be wired in in the same way as the conventional actuator, or are there more control wires, and hence a need for a new CH/HW controller as well?
Much appreciate your guidance on this as I am fed up with changing conventional actuators every year or two.