Variable speed blowers

[h20 stove]

I am trying to find info on some of the new variable speed furnaces and heat pumps on the market. More specifically, I am wanting to know how to connect an extra fan relay so that the blower will run on high speed instead of half speed. I install waterstoves to existing furnaces. I normally break the fan(green) wire from the thermostat through an NC terminal on a relay and power the fan with the corresponding NO terminal to prevent backfeed to the thermostat and energize "G" on the terminal strip. According to some folks I have talked to, on the new variable speed units, the "G" terminal will only bring the fan up to half speed. How can I hook up an extra relay and bring the fan up to full speed? I realize that every manufacturer will probably have a different way, but I'm hoping they will be similar.

[beenthere]

Even though you are a contractor.
This type of instruction is not allowed to be given out in the open resi forum.

Home owners could try it themselves, and damage something.

But its really easy to do what you want.

[AcDOCnTRAINING]

update to pro status and will talk

[beenthere]

He needs more post before he can apply.
I think it 15 post to apply.

[h20 stove]

I'm working on the posts. will be there soon. Thanx

[nubbin]

beenthere? 16,411 posts? do you have writer's cramps yet? Makes me feel 'un-helpful' ;^)

[beenthere]

LOL.

Only about 11 post a day.

And some of them are just , Yep, or nope, post.

[nubbin]

just a 'yep', well keep it up. I have some customers who think "Yes, because" is too much info:-)

[RoBoTeq]

beenthere? 16,411 posts? do you have writer's cramps yet? Makes me feel 'un-helpful' ;^)

Ridiculous, ain't it?

[mark beiser]

I wouldn't call them "new", unless you consider something that has been in use for 2 decades "new".

Without getting to technical, the Y(Y2) terminal, and a double pole single throw relay, with a set of NO and a set of NC contacts, are your friends.