Daikin VRV wiring adapter board

[mchild]

I am installing a Daikin VRV system in my home. I have ordered the KRP wiring adapter boards for each of the FXSQ ducted air handlers. The primary reason for the adapter boards is to help control a back up heating system.

I have noticed on the boards that there are two terminals labeled as (Y3 & Y4) Humidity Control and a switch on the board for turning on and off the Humidity Control input.

The instructions do not discuss this portion of the board and for the purposes of connecting a humidifier there are instructions that uses other terminals on the board.

So, it would seem as though the terminals in question may have to do with de-humidification. Does anyone know what these terminals are for and how they can be used?

Also, on this adapter board there is a connector at one corner next to two fuses labeled as X1A/CN1 that is jumpered together (two pin connector). Does anyone know what this controls and the purpose of it be jumped?

[coolbone69]

what type vrv?is it a krp1b61 pcb?as this board does not connect to vrvIII m/p series

[mchild]

what type vrv?is it a krp1b61 pcb?as this board does not connect to vrvIII m/p series


I am in the U.S. and we have the VRV-S model that is not based on the VRV III. The board as it is known here the KRP1B71. I believe it may be the same as EKRP1B2 or KRP4A51.

Any help is appreciated.

[frank]

The KRP2A is suitable for VRV comms.

The KRP4A is suitable for Sky Air comms.

The 2 are not interchangeable.

You need 1 KRP4A board for each fan coil with a controller attached or multiple fan coils with 1 controller controller attached on Sky Air, but you can remote stop start the whole VRV system with 1 KRP2A on the outdoor unit no matter how many indoor fan coils are connected.

If you fit a KRP2A to an indoor fan coil on a 3 pipe VRV system then you only control that fan coil.

[mchild]

The KRP2A is suitable for VRV comms.

The KRP4A is suitable for Sky Air comms.

The 2 are not interchangeable.

You need 1 KRP4A board for each fan coil with a controller attached or multiple fan coils with 1 controller controller attached on Sky Air, but you can remote stop start the whole VRV system with 1 KRP2A on the outdoor unit no matter how many indoor fan coils are connected.

If you fit a KRP2A to an indoor fan coil on a 3 pipe VRV system then you only control that fan coil.


Thank you Frank.

Yes, I have the U.S. equivalent to KRP2A (EKRP1B2A) to be used on FXSQ air handlers and a single two pipe VRV-S RXYMQ out door unit. The primary function of these boards is to facilitate the operation of electric heaters in the duct for supplementing the system and providing heat in emergency if the Daikin unit is not functioning.

One of the other members has emailed me the manual which describes all functions of this board. Here in the U.S. there is little to no information readily available on the board so this manual is helpful.

To use this board to operate electric duct heating for times when the system can not maintain the set point you can connect to terminals YC and Y1. I have heard (it was not in the manual) that those connections close at 4*C below the set point on the controller and reopens at 2*C below the set point. Thus, it turns the supplemental heat on at 4* below and back off at 2* below the controller set point.

I am trying to determine how to adjust that to a more reasonable temperature spread so that the rooms do not have to get so cold before the electric heat comes on and then keep the electric heat on until the set point has been reached.

Any help that you can provide would be greatly appreciated.

[brunstar]

that board will make the contacts when the indoor unit fan is running, if you have a heater connected to it you will also have to have a secondary safety to stop the heater if the fan stops..

[frank]

that board will make the contacts when the indoor unit fan is running, if you have a heater connected to it you will also have to have a secondary safety to stop the heater if the fan stops..

Be careful here - the pcb contacts are only rated up to 1 amp, so, if you want to control an electrical resistance heater you must use a secondary relay or contactor that has a higher rating.