Heating Help

Baxi Luna 24fi motherboard issues?

Hey there - I recently bought a stacked townhome in an urban area.  The heat and hot water is controlled by a Baxi Luna 24fi system which is a rental unit from a local company (Direct Energy and Enbridge) in Toronto, ON, Canada.  One of the draws of rental is that you don't have to worry about service issues.
.... Or so I thought.
Our heat went out the other morning and I called in the tech's.  Before even looking at the unit, they told me "this could be bad".  Apparently, there is an issue with a circuit board on the Baxi Luna 24fi which causes the pressure to drop off and the system stops working.  The tech's indicated that this part is no longer available, and thus I would likely need a new unit.  He said they don't offer "rental" on a unit that would fit (without significant infrastructure changes) so I would have to buy a new Baxi Luna 310 (unit and installation) at a cost of $7,000!
Does this pass the sniff test?  Is there any credibility to the claim that the circuit boards can't be replaced and I am on the hook to buy a new $7K unit?  Would I be better to try and have someone look at the unit and repair it who ISN'T the rental company (knowing full well that I don't own the unit, and really shouldn't be meddling with it).
I appreciate your help.  I just want to know if there is any truth to this claim that it is an unfixable problem!
Thanks.

Something smells funny...

I've never heard of a solid state electronic control board causing a loss of pressure. I have heard of a low pressure condition causing the heat source to lock out, but all it takes is to re-pressurize the system to overcome this problem.

I have also completely replaced the on board control logic/wiring harness on numerous different brand of high efficiency boilers. Provided that the heat exchanger and other components are in good shape, you SHOULD be able to replace the logic without replacing the appliance, IF it is necessary.

On the outside, it would appear that someone is trying to take advantage of you, but I do not have ALL of the facts...

ME

If I was in your spot

I'd go back to the " rental/ owner " company and start again. I'd request the dept manager. Make sure you have model/ser # available. I'd contact Baxi directly to see if parts are in fact available for that unit prior to calling them again. Make sure you know who you are talking to for follow-up calls, if necessary. Good luck!

maybe the other way around?

sounds like its the sensor that 'sees' the pressure that's bad.  so you could say the system losses pressure in a backward way, when really the board stops seeing pressure.

Motherboard problems

I also have a Baxi unit (not sure which). We've had service technicans come frequently. They told us the exact same thing regarding the motherboard. I've lived in two townhomes here and ahd the same problems in both.
Other people in my complex (near King and Strachan) have also had hot water issues related to the motherboard or insignificant line pressure drop to cause the burner to kick in.

One trick we've found useful is to turn the furnace on, which turns on the burner, before starting the shower? (Pretty stupid, but it works for the short term)