Constantin
Well-known member
So some of you may remember some noises I made way back when about remanufacturing a Energy Recovery Ventilator in this house. It's actually a hybrid, featuring a ERV and HRV core, manufactured by Lifebreath as the TRV series way back in the 2000's. Anyhow, this one is configured as a fart fan, pulling air out of the bathrooms and putting fresh air back into the return ductwork on the AC system. Problem is, the control system in the unit was so user friendly that I am replacing it.
At the heart of the problem is that the motion-activated sensors in the bathrooms (24VDC on/off) only enable one response, full-on (!!!). That may be appropriate in some households with constant gastro-intestional distress issues, not so much here though.
Between toddling kids, cats, and so on, my wife got woken so many times that I had to disable this system. So, the first phase was to strip out the OEM PSC motor, control board and assorted junk. Then I added two hyper fans (ECM), one pulling air out of, the other pushing air into the house. These fans are speed-controlled using two optically-isolated resistance ladders with 8 inputs, i.e. 256 combinations (2.2k, 1.1k, and so on).
In order to balance the in vs. out air flow, the Lifebreath I&O manual wants you to use a manometer and adjust a damper to get to zero delta-P. Naturally, my original HVAC contractor didn't do that (One OEM once joked to me that most contractors use manuals solely as knee pads). I hope to achieve the same effect minus the manometer by using two Wind meters from Modern Devices to balance the air flow. So one blower gets up to speed, then the second one is ramped up until it achieves the same wind speed in the opposite direction.
Inside, a set of four DHT22's monitor the humidity and temperature of the incoming and exiting air streams. Eventually, I want to use this unit not just as a fart fan / TRV but also as a economizer. But that's some time away, just as hooking up a Nextion display / controller and a ESP12 for communications with the whole house DAQ. Today, the control daughter-board arrived from Laen, so hopefully a 3.2 will be running this ERV soon. Pictures to follow. Cheers!
PS: Seem to be much more successful with TRV so far than getting home fiber optic network running. Bummed I am, it appears that the structured cabling I had installed by an electrician way back when was sufficiently manhandled to break the fibers despite multiple layers protecting them (i.e. outer jacket cable bundle in addition to the jacket around the OM1 fiber pair). Out of the four fibers going into the office, only one reports a 23db loss (!!!) the rest of them have more than 50db loss (i.e. are likely write-offs). FWIW, I'm not blaming the electrician, any number of reasons could have led to that series of failures. I'll re-confection the office connectors, just in case, but I suspect fiber breaks elsewhere.
At the heart of the problem is that the motion-activated sensors in the bathrooms (24VDC on/off) only enable one response, full-on (!!!). That may be appropriate in some households with constant gastro-intestional distress issues, not so much here though.
Between toddling kids, cats, and so on, my wife got woken so many times that I had to disable this system. So, the first phase was to strip out the OEM PSC motor, control board and assorted junk. Then I added two hyper fans (ECM), one pulling air out of, the other pushing air into the house. These fans are speed-controlled using two optically-isolated resistance ladders with 8 inputs, i.e. 256 combinations (2.2k, 1.1k, and so on).
In order to balance the in vs. out air flow, the Lifebreath I&O manual wants you to use a manometer and adjust a damper to get to zero delta-P. Naturally, my original HVAC contractor didn't do that (One OEM once joked to me that most contractors use manuals solely as knee pads). I hope to achieve the same effect minus the manometer by using two Wind meters from Modern Devices to balance the air flow. So one blower gets up to speed, then the second one is ramped up until it achieves the same wind speed in the opposite direction.
Inside, a set of four DHT22's monitor the humidity and temperature of the incoming and exiting air streams. Eventually, I want to use this unit not just as a fart fan / TRV but also as a economizer. But that's some time away, just as hooking up a Nextion display / controller and a ESP12 for communications with the whole house DAQ. Today, the control daughter-board arrived from Laen, so hopefully a 3.2 will be running this ERV soon. Pictures to follow. Cheers!
PS: Seem to be much more successful with TRV so far than getting home fiber optic network running. Bummed I am, it appears that the structured cabling I had installed by an electrician way back when was sufficiently manhandled to break the fibers despite multiple layers protecting them (i.e. outer jacket cable bundle in addition to the jacket around the OM1 fiber pair). Out of the four fibers going into the office, only one reports a 23db loss (!!!) the rest of them have more than 50db loss (i.e. are likely write-offs). FWIW, I'm not blaming the electrician, any number of reasons could have led to that series of failures. I'll re-confection the office connectors, just in case, but I suspect fiber breaks elsewhere.
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