HRV Controls

BigGeorge

Does anyone with a HRV or knowledge of these systems have advice on the setup of controls for such a system in a large airtight house. All the manufacturers are selling the boxes but am not clear on how you would need to control it practically

e.g. should showerrooms / kitchens have a boost button or a humidity sensor
should summer bypass be automatic etc....

RVR

There are two types of system on the market from my (our) experience. FYI, we have supplied both types so have experience of both systems.

1. Units with backward curved fans which offer excellent efficiency on paper but are difficult to control, balance, etc. These systems usually use core grilles which need to be manually screwed in and out to control airflow. These grilles can not be automatically controlled - hence the control issues.

2. Units with forward curved fans - an extract rate is set for the house according to building regs, and the unit automatically adjusts fan speed to maintain this extract rate / pressure at all times. These systems typically use self balancing grilles which have humidity and/or motion detection. The nature of forward curved fans make these marginally less efficient but it is a more elegant, better controlled system.

So make sure you look around and find all the alternatives. Google MVHR (Mechanical Ventilation with Heat Recovery) as well as HRV!!!

Cheers

Des

BigGeorge

Thanks Des, the title should of course said MHRV.

Have any users of MHRVs got any feedback on the controls?

gizmo555

BigGeorge wrote: »

Thanks Des, the title should of course said MHRV.

Have any users of MHRVs got any feedback on the controls?

My system controls are pretty much as you describe. There are "boost" switches in the kitchen and at the bathrooms which increase the airflow. The boost is on a timer and goes back to normal low speed operation after about 20 minutes. There is no humidity sensor.

Summer bypass is automatic and kicks in when the external temperature is over 14C.

Technophobe

Hey gizmo

what make is the one you have?..sounds good...

gizmo555

Technophobe wrote: »

Hey gizmo

what make is the one you have?..sounds good...

PM sent . . .

Lightning McQue

Gizmo

Could you pm me as well.

Thanks.

Lightning

gears

Aren't boost controls not pretty standard in any modern MVHR. Most I've looked at have them as either room switches or more conviently, I think, built in to a humidity sensor.

gizmo555

Lightning McQue wrote: »

Could you pm me as well.

Done

gears wrote: »

Aren't boost controls not pretty standard in any modern MVHR. Most I've looked at have them as either room switches or more conviently, I think, built in to a humidity sensor.

I suppose a humidity sensor would be no harm, but I would think it would be best as an addition to a manual switch, not as a substitute.

For example, when I'm going to have a shower, I usually hit the boost switch a couple of minutes before I start the shower. This means the faster airflow is already moving well when the extra humidity starts to be produced. If the system relied on a sensor, there would be an inevitable lag between the humidity starting to increase and the increased ventilation kicking in.

Also, I would want to be able to override the sensor, in case of faults, or to guarantee that it wouldn't, say, crank up the ventilation to full tilt late at night when I'm dropping off to sleep.

Frankly, I haven't missed having a sensor and I'm happy that for me it's a good example of K.I.S.S.

gears

I should have clarified that any I've seen also had a manual switch some with a remote control so you could do all the controlling yourself but with the addition of the humidity sensor which takes away some of the thinking, which for some might be too much to think of actually having to turn on the boost before having a bath or shower.