Relay question

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OK. Next in the ongoing saga of plumbing in our MVHR system.

I have the following issue.
We are installing an MVHR system, which has a low/med/high fan speed run by a remote, wired in switch. All fine, and I asked before how to wire it in, and am doing so with a .75mm yy cable.

BUT... I'd like to run the unit to high if a shower produces an amount of humidity. I can put in a sensor which runs out a line and neutral, but I actually want the switch, three showers and two heat sensors to ALL optionally run the fan on high.

When I turn on the high speed I don't need to turn off the lower speed.

I've worked out that I need a relay, with up to six inputs and one output. But I can't find one online, or, rather, it's likely I'm not looking in the right place.

Help? Please?
 
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OK. Next in the ongoing saga of plumbing in our MVHR system.

I have the following issue.
We are installing an MVHR system, which has a low/med/high fan speed run by a remote, wired in switch. All fine, and I asked before how to wire it in, and am doing so with a .75mm yy cable.

BUT... I'd like to run the unit to high if a shower produces an amount of humidity. I can put in a sensor which runs out a line and neutral, but I actually want the switch, three showers and two heat sensors to ALL optionally run the fan on high.

When I turn on the high speed I don't need to turn off the lower speed.

I've worked out that I need a relay, with up to six inputs and one output. But I can't find one online, or, rather, it's likely I'm not looking in the right place.

Help? Please?
So It's all sensors and one switch?
Is the output on the sensors a relay contact?
 
Last edited:
Or 1 relay with 120,v coil, stick diodes in the 240v lines to the relay & a cap to N after the diodes to smooth it out a bit.
Sounds like an Arduino job to me :)
 
I think we need to find out what the sensors are capable of and how they work before we offer advice.
 
Sunray's suggestion is very sensible, if all the sensors have outputs that are voltage free contacts then it might be that a relay will not be needed
 
The reason I ask is I have encountered humidistats with:
2 wires and require a fairly specific 110V relay,
3 wires with a solidstate output from 'L'.
4 wires with real voltfree contacts.
4 wires with solidstate VF contacts rated for ELV and some of those have very limited current.
4 wires which output 24V DC.

All of which need to be handled differently.
 
The sensors are xh-w3005 humidity sensors and put out 240v line and neutral when on.
The switch is from Boulder and is like this:
DHV-04-100B-Wiring-pdf-1024x850.jpg
The multiple relay looks good but really I dare say I just need a relay triggered and then putting out power when on for line power from any of the sensors or the switch.
 
If your sensors are as described, are only connected to your central system and don't object to the output going live when they are inactive then yes you can connect them all in parallel to a relay that REPLACES k2 in your drawings.
Otherwise some buffering is required.
Note that relay k2 switches power from one motor tap to a different motor tap so a relay or switch in parallel with the outputs of k2 will not work properly.
 
Note that relay k2 switches power from one motor tap to a different motor tap so a relay or switch in parallel with the outputs of k2 will not work properly.

And is likely to cause damage as part of the winding would be shorted out. Don't do this!

You'll need to have a changeover contact on one relay controlling the MVHR, all the other inputs need to switch this (probably through more relays)
 
If your sensors are as described, are only connected to your central system and don't object to the output going live when they are inactive then yes you can connect them all in parallel to a relay that REPLACES k2 in your drawings.
Otherwise some buffering is required.
Note that relay k2 switches power from one motor tap to a different motor tap so a relay or switch in parallel with the outputs of k2 will not work properly.
And is likely to cause damage as part of the winding would be shorted out. Don't do this!

You'll need to have a changeover contact on one relay controlling the MVHR, all the other inputs need to switch this (probably through more relays)

Based on the information gleaned so far and making some assumptions:
IF the drawing of the DHV-04/100B is accurate & complete and it has 2 motors as it appears, then the above advice [in black] is incorrect and I see no problem to the motors to apply mains voltage to both high and low simultaneously.

Typically 2 speed motors will have 2 'taps' as described above but these appear to simply have series capacitors to run on a reduced speed.

The pictures of the xh-w3005 sensor clearly show a relay with Thick PCB tracks from under the relay [presumably only to the relay contacts] to the input and output wires, implying that there is not an expected problem with running several sensors in parallel.

I must stress that from this distance I can't guarantee my advice is correct but based on far from complete information or any form of testing I don't forsee any problem with connecting multiple yellow wires to 'H' terminal.

HOWEVER there will be a full 230V coming out of 'L' terminal and you would have to verify that will not cause any problems to whatever is connected to it. Equally when running in low speed a voltage, possibly approaching full mains voltage, will be coming from 'H' terminal.
 

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