Versatemps - Operating new and old types as master and slave

[Refrigerologist]

Hi all,

We have a building that is operating a large number of R407C EVH15 to 24 ceiling void units. Many of these are operating as master and slave. Quite a few are operating with different capacity versions operating in this manner, e.g. a size 21 and a size 15 are operating from a single controller with the dip switch on the smaller unit(s) being set as slave.

Clivet have introduced a new R410A EVH**X units, but these are only available up to size 17.

We have a couple of size 15 units that have failed and we wish to install new replacements. The problem is that these 2 units operate in a common ductwork system and have size 21's blowing though the same supply air duct.

Clivet UK have told us that it is not possible to 'link' the old units and new units as master and slave. They have suggested that we separate the units and operate each from individual remote controllers. This is not going to be possible due to the common ductwork arrangement and the possibility of each controller being in a different mode.

The layout of the ductwork does not allow for easy separation as each Versatemp blows into a plenum at the start of the ducting and this does not split until quite a distance into the room. The worst of it is the client carried out a refurbishment of the building, but did not upgrade the A/C. Removing ceilings to install new ductwork is not going to be popular or likely. The offices are now fully occupied.

I have yet to see a wiring diagram or full set of installation instructions, so I do not know if what I have been told is categorically correct. Hopefully, if it is true there may be a work around, by installing additional relays and volt free contacts. The alternative is to scrap some 8 year old units and replace fully serviceable units in groups of 2 or 3. Obviously my client isn't a happy bunny at the thought of that.

Cheers in advance for any ideas.

[monkey spanners]

Can you fit the new control system to the older units and then use a new remote?

[Refrigerologist]

No, the 2 systems are not compatible.

[monkey spanners]

Can you put move the old but working ones of failed pairs together to get a good master slave set up on an old controller and then put two new ones on a new control?

[Refrigerologist]

Not possible as we have robbed the board off of this one to make one good one already. There are no other units that can robbed.

In any case, going forward, this problem is going to occur many times.

Clivet are poor to have designed something that cannot be linked to their old units. Especially as they have updated only half of the range.

[The Viking]

I believe what Mr Spanners said is to make the best out of a bad situation.

When an old unit fail, replace both units in that pair with new units. If you then are left with an old but working unit you can then use that working unit as a spare for the next old unit that fail and then just repeat this process until the whole building got new units.

However, long term it is likely that your customer would see financial gains in replacing the whole lot for something more modern, like VRV/VRF. Sadly in todays accountant driven world customers only look to the next financial year end instead of long term...

[Refrigerologist]

Viking, that would really be helpful if we had more than one faulty unit, but we don't. As the client replaced half of the units in 2008 and the other half in 2016 I don't think they will be too happy to replace the system, regardless of whether they are accountants or not.

Why is VRF more modern? It has its own problems with the quantities of refrigerant and small rooms requiring leak detection monitoring. To be honest I could do without the lectures about what I could do if I had spare broken units or hundreds of thousand of pounds to spend.

Water loop heat pumps are still a current solution, and VRF is not appropriate for all buildings and sites. We have major problems with noise abatement and Versatemp systems actually avoid that problem in the main, as we only require dry air coolers or adiabatic assisted dry air coolers to be placed outside, or inside with the appropriate design.

My company installs and maintains a wide variety of equipment, which includes 4-pipe chilled water and hot water systems, VRV/VRF systems as well as splits and Versatemps.

I would appreciate it if you could keep your replies on topic, which is: "is there a way to link the old Versatemp units to the new Versatemp units to allow a master/slave set up.

If it is not possible, we will have to replace 2 units at a time. We can then hold onto the good removed unit and repair faulty unit and use these to replace any other units that fail. We are trying to avoid this situation as the client carries an insurance, whereby they receive a large portion of the value of a unit that is replaced and nothing for a repair. So there is a dilemma for him, not so much for me, but I am duty bound to do my best for the client.