Rheem fan speeds....?

[faithfulfrank]

Hi everyone. I have a house that has radiant floor heating with a boiler. I am in the process of adding whole house A/C. I am using a rheem RHKA variable speed air handler. (Prestige series)

What I want to know is this......
Can I set this up so that the fan can constantly run at a low speed, just for air filteration, and only ramp up to full speed when the thermostat calls for heat or cooling?

I am also adding a heating coil off an extra zone off the boiler, so when I need only a small amount of heat, say during the spring/fall.

I called rheem, and the two people I spoke to were not too helpful. I understand that the thermostat settings can be made for constant on, but can the air handler run continuously on a very low speed and onlty ramp up for heating and cooling?

I also want to add a american standard clean effects filter. It would be great to run the air handler all the time on low speed to get continous filteration.

I read somewhere that you can run these on a low speed for only $14.00 per year. It does not make much sense to spend money on a good filteration system, and only be able to run it during heating or cooling.

My friend who is a air balancer thinks I can do this, but is not sure.

Thank you in advance for your kind help.

Frank D.

 

[AbbyNormal]

Their modualting gas furnace operates that way, perhaps call the installing contractor to properly set the dip switches for you.

 

[faithfulfrank]

thank you. I thought it was just a question of setting the correct dip switches.
I would think that this is a common type of running situation. That is why I upgraded to a variable speen blower unit.

One more question, If I may.

I'm told that it is good to have a TXV, thermal expansion valve. Is that on the compressor or the air handler, and what do I look for to see if I have it? I read all my paperwork, but there is no mention of it.
If I don't have it, do I want one, and could I get one? Is it worth it? I live outside of buffalo NY, so we have a wide range of temps here.

I built my own house, but am not that knowledgeable on this A/C stuff.

Thanks again.

Frank D.

 

[MikeHalloran]

I think a TXV would be inside the air handler, at the high pressure connection, right where you'd ordinarily find an orifice or a capillary tube. If you had one, they'd probably brag about it. I'm not convinced you need it anyway.

Bank the money the VS motor saves. You will need it, and more, to replace the motor when it dies.



Mike Halloran
Pembroke Pines, FL, USA

 

[faithfulfrank]

Thanks Mike,
Yes, I'm told they are expensive to replace. I plan on selling and retiring in 10 years or so..hopefully i'll beat that expense. The whole air handler was around $800 bucks and change.....

I was also told that since my lineset is about 33 feet, I probably do not need a TXV......at least now I know where to look.

I built this house 6 years ago, and started on putting in a regular furnace/ac unit, but was then talked into installing radiant floor heat. I like it, but I wish I followed my original plan. It's a bear cutting in runs in a already built house.

Thanks again, Frank D.

 

[MikeHalloran]

My ICP air handler came with an Emerson VS motor and a five year warranty. Died at six years. Best quote so far; $1200 for a replacement motor or $900 for an entire air handler with VS motor. It's a world gone mad.

My wife's cousin did radiant floors by stapling the tube to the bottom of the subfloor, working in the crawlspace. Not much fun, but the result was nice.



Mike Halloran
Pembroke Pines, FL, USA

 

[AbbyNormal]

that is a higher 'SEER" air handler with an ECM motor, so it will have a TX valve.

You mention heat so not a primarily cooling environment. That constant fan tends to re-evaporate moisture and raise RH in the cooling mode. Worse when the air handler is installed horizontally. Sort of an 'adibiatic saturater'

Perhaps your climate is dry enough in the summer where humidity is not a big issue.

 

[faithfulfrank]

Thanks Mike and Abbynormal.....!

My thinking is that I wanted primarly A/C, but since I was putting in the air handler, ductwork, etc, and I have an unused zone off my boiler, whats another $200 bucks for a hot water coil?
I like my radiant floor heat, but I have a few rooms that give me problems...two bedrooms that have a higher outside wall fottage with a smaller footprint for the radiant floor heat. these rooms are cold in the winter.

My great room has alot of solar gain, and gets hot even in the winter.
Having the aux heat from the heat coil could give me additional heat for those two bedrooms, and running the fan constantly could balance out that hot air in the great room and spread it to the other rooms, I'm thinking.

In the summer here the humidity avg. about 75%.......lower during our fridgid cold winters. My house is pretty tight, so I've never needed a humidifier....almost the opposite sometimes.

Thanks guys. Does any of my plans sound wrong to you. or do you have any other suggestions?

Thanks again. Frank D.

 

[AbbyNormal]

The constant fan even outs the temperatures in the winter, I was just pointing out that can cause elevated indoor humidity in the cooling season.

A dry house is a drafty house. If you are getting window condensation in the winter,you need some more ventilation.

Take the "V" out of HVAC and you have a HAC (hack) job.

 

[faithfulfrank]

"Take the "V" out of HVAC and you have a HAC (hack) job."

that's good. I'll have to tell that to my air balancer friend. He is helping me with this project.

I do not get very much condensation, but some on the coldest nights,,,,we're talking well below zero here.

I built the house solid and tight, but put good fans in, and have checked my boiler for backdraft having all the fans on.....it was ok.

I'l watch that humidity thing in the summer. Perhaps I would not run it constantly all the time. I'm currently looking at different thermostats that give me that option.

thank you for the good help.

Frank D.

 

[AbbyNormal]

You're welcome

The 'fan/auto' switch is a standard thing on a heat/cool thermostat

I grew up north of Minnesota, I know cold, so well that I moved way south. The humidity issue is probably nothing for you to worry about in the summer. Its quite significant down here.