A little off topic, but you guys are smart, perhaps you have some ideas.

I have a 6 month old bungalow in Ottawa, Canada. It is equipped with a
forced air Bryant model 340MAV natural gas furnace, a Bryant 593C a/c and a
Venmar model 4100 ventilator.

I like to run the circulation fan on low speed continually, especially in
the summer and winter. The furnace controller does not provide for a third
speed to be selected controlled by the thermostat on-auto fan switch even
though the fan motor is 4 speed. Does any one see any major hazards in
adding a double throw, 3 pole relay to allow running the fan at a low speed
when selected at the thermostat and enabling the two highest speeds for a/c
and heat when there is call for temperature change.

The Venmar ventilator is installed with a humidistat for control. I don't
think much of this because in the winter when all is closed up and the
humidity is low it never comes on, just when you would like some fresh air.
I propose to control this by a programmable timer switch. Any thoughts?
Additionally it collects air from ceiling level on the main floor and dumps
fresh cold into the basement, my shop area. What if I connect the fresh
cold into the furnace cold air plenum and wire the furnace fan to run at low
speed whenever the ventilator is on. More thoughts?

Perhaps there is a much better scenario than this that will not cost an arm
and a leg.

Comments and suggestions (serious) please.

Thanks, John.

"John Wilson" wrote in message
. ..
A little off topic, but you guys are smart, perhaps you have some ideas.

I have a 6 month old bungalow in Ottawa, Canada. It is equipped with a
forced air Bryant model 340MAV natural gas furnace, a Bryant 593C a/c and
a
Venmar model 4100 ventilator.

I like to run the circulation fan on low speed continually, especially in
the summer and winter. The furnace controller does not provide for a
third
speed to be selected controlled by the thermostat on-auto fan switch even
though the fan motor is 4 speed. Does any one see any major hazards in
adding a double throw, 3 pole relay to allow running the fan at a low
speed
when selected at the thermostat and enabling the two highest speeds for
a/c
and heat when there is call for temperature change.

The Venmar ventilator is installed with a humidistat for control. I don't
think much of this because in the winter when all is closed up and the
humidity is low it never comes on, just when you would like some fresh
air.
I propose to control this by a programmable timer switch. Any thoughts?
Additionally it collects air from ceiling level on the main floor and
dumps
fresh cold into the basement, my shop area. What if I connect the fresh
cold into the furnace cold air plenum and wire the furnace fan to run at
low
speed whenever the ventilator is on. More thoughts?

Perhaps there is a much better scenario than this that will not cost an
arm
and a leg.

Comments and suggestions (serious) please.

Thanks, John.


Sounds like you need to control this with a PLC. You can probably pick one
up for less than $200. Then it is just a matter of programming it.

Shawn

"Shawn" shawn_75ATcomcastDOTnet wrote in message
...

"John Wilson" wrote in message
. ..
A little off topic, but you guys are smart, perhaps you have some ideas.

I have a 6 month old bungalow in Ottawa, Canada. It is equipped with a
forced air Bryant model 340MAV natural gas furnace, a Bryant 593C a/c and
a
Venmar model 4100 ventilator.

I like to run the circulation fan on low speed continually, especially in
the summer and winter. The furnace controller does not provide for a
third
speed to be selected controlled by the thermostat on-auto fan switch even
though the fan motor is 4 speed. Does any one see any major hazards in
adding a double throw, 3 pole relay to allow running the fan at a low
speed
when selected at the thermostat and enabling the two highest speeds for
a/c
and heat when there is call for temperature change.

The Venmar ventilator is installed with a humidistat for control. I don't
think much of this because in the winter when all is closed up and the
humidity is low it never comes on, just when you would like some fresh
air.
I propose to control this by a programmable timer switch. Any thoughts?
Additionally it collects air from ceiling level on the main floor and
dumps
fresh cold into the basement, my shop area. What if I connect the fresh
cold into the furnace cold air plenum and wire the furnace fan to run at
low
speed whenever the ventilator is on. More thoughts?

Perhaps there is a much better scenario than this that will not cost an
arm
and a leg.

Comments and suggestions (serious) please.

Thanks, John.


Sounds like you need to control this with a PLC. You can probably pick one
up for less than $200. Then it is just a matter of programming it.

Shawn

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~

Google suggests that PLC means Programmable Logic Controller, so I assume
this is what you refer to.

John.

"John Wilson" wrote in message
...

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~

Google suggests that PLC means Programmable Logic Controller, so I assume
this is what you refer to.

John.

A quick search found this one, T1000MD888+ for ~$200.
http://www.tri-plc.com/t100md.htm There are many others like this one out
there. This could accept the inputs from the humidistat, thermostat and
even an outdoor thermometer and then using the outputs, control the
ventilator and furnace fan. BUT, you'd need to program it from the ground
up. This may or may not be a problem for you. If you learn how to program
well, you could set this thing up to be the ultimate
thermo-humidi-ventilatorstat.

Shawn