Hoping someone can offer some guidance. I do want to state that I will not
be doing the work myself but will have a licensed electrician replace the
motor in my unit heater if it is a good option. I am asking here instead of
playing phone tag with the electrician and waiting two weeks for a call back
plus I know there are a lot of experienced folks here that can tell me if
I'm thinking in the right direction.


Here's the question:

I have a Reznor vertical hydronic unit heater model hh-175. It's currently
used for on-demand heating of a garage. The heater has a 1/30 hp motor that
turns at 1550 rpm's. Problem I'm having is that the heater puts out some
decent heat and raises the temp of the room but not quite enough to overcome
the drafts in the old building when it's really cold out. The hot water to
the heater is about 190 degrees which according the heater manual produces
about 60k btus at about 550 cfm. The hot water return on the heater is still
extremely hot so it appears that the heater does not deplete the heat from
the coils all that much. What I'd like to do is put a larger motor on it to
try and increase the cfm's to use more of the heat that appears to be
available. Doing the also may increase air circulation in the room to spread
the heat around a bit more also. Does this sound like a good or a bad idea
?

Thanks,

Mark

"Mark" wrote in message
...

Hoping someone can offer some guidance. I do want to state that I will not
be doing the work myself but will have a licensed electrician replace the
motor in my unit heater if it is a good option.

Not hard to do for a DIY. I used to run the assembly line for unit heaters
that compete with Reznor.

I am asking here instead of
playing phone tag with the electrician and waiting two weeks for a call
back
plus I know there are a lot of experienced folks here that can tell me if
I'm thinking in the right direction.


Here's the question:

What I'd like to do is put a larger motor on it to
try and increase the cfm's to use more of the heat that appears to be
available. Doing the also may increase air circulation in the room to
spread
the heat around a bit more also. Does this sound like a good or a bad
idea
?

Bad idea.

Changing the motor is not going to give more CFM unless it turns at a higher
rpm. A 1/30 hp motor at 1550 will give the same volume of air as a 1/2 hp
motor at 1550 with the same fan blade. I cannot speak for Reznor, but we
used to offer two fans on a given model, one had a higher output. There
were still limits as to the amount of heat that a given coil will produce.

Increasing the flow of air over the coil is not necessarily going to extract
more heat. You need a certain amount of "residence time" for the moving air
to pick up the heat from the surface area of the coil/fins. It may move it
to other sections of the room, but it is not going to give off more heat.
You can get the same result by putting a secondary fan to help move the air
to where it is needed.

In truth, you can get more heat from the coil with lesser air flow. That
gives the air more time to pick up the heat. What it also does is reduce
the circulation. It will be much hotter at the heater, but much cooler in
the far areas of the room.

When I worked for the Nesbitt Company years ago, we had some pretty smart
engineers trying to wring out as much heat as possible from a given heater
design. You need some balance between air flow and temperature. I'm sure
Reznor did the same.

If you want to get more heat out of the water line in the room, add more
surface area. After the heater add sections of finned tube. Or add a
second heater with blower.
Ed

http://pages.cthome.net/edhome

"Mark" wrote in message
...

Hoping someone can offer some guidance. I do want to state that I will not
be doing the work myself but will have a licensed electrician replace the
motor in my unit heater if it is a good option. I am asking here instead
of
playing phone tag with the electrician and waiting two weeks for a call
back
plus I know there are a lot of experienced folks here that can tell me if
I'm thinking in the right direction.


First, I would not hire an electrican to do a HVAC techs work.


Here's the question:

I have a Reznor vertical hydronic unit heater model hh-175. It's currently
used for on-demand heating of a garage. The heater has a 1/30 hp motor
that
turns at 1550 rpm's. Problem I'm having is that the heater puts out some
decent heat and raises the temp of the room but not quite enough to
overcome
the drafts in the old building when it's really cold out. The hot water to
the heater is about 190 degrees which according the heater manual produces
about 60k btus at about 550 cfm. The hot water return on the heater is
still
extremely hot so it appears that the heater does not deplete the heat from
the coils all that much. What I'd like to do is put a larger motor on it
to
try and increase the cfm's to use more of the heat that appears to be
available. Doing the also may increase air circulation in the room to
spread
the heat around a bit more also. Does this sound like a good or a bad
idea

Bad.
The other post repeats about what I was going to say..


?

Thanks,

Mark

Hi,

190 degrees is very hot. Most hydronic heating systems are run about 140
degrees. Make sure your fan coils are clean also. I like your idea. You should
have a ten degree difference in the temp of the incoming and outgoing water in
the loop. I would increase the flow and drop the temp if it were me. This can
be done with a higher horse motor and a fan with a higher flow rate of air. The
pitch on the blades can increase the ccf. You'll need a different motor of the
same rpm with at least a 1/15 hp.

candice

Hi CLSSM00X7, hope you are having a nice day

On 02-Dec-03 At About 02:01:07, CLSSM00X7 wrote to All
Subject: Hydronic Unit heater motor question.

C From: (CLSSM00X7)

C Hi,

C 190 degrees is very hot. Most hydronic heating systems are run about
C 140 degrees.

Wrong as usual. most residential systems run at about 180 degrees.

C Make sure your fan coils are clean also. I like your
C idea. You should have a ten degree difference in the temp of the
C incoming and outgoing water in the loop. I would increase the flow
C and drop the temp if it were me. This can be done with a higher
C horse motor and a fan with a higher flow rate of air. The pitch
C on the blades can increase the ccf. You'll need a different motor
C of the same rpm with at least a 1/15 hp.

All wrong. you really need to stop trying to answer these questions.



-= HvacTech2 =-


... A miser is hard to live with, but makes a fine ancestor.

___ TagDude 0.92á+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

"CLSSM00X7" wrote in message
...
Hi,

190 degrees is very hot. Most hydronic heating systems are run about 140
degrees.

Wrong.
Try 190 is about right...res units run between 180-195F


Make sure your fan coils are clean also. I like your idea. You should
have a ten degree difference in the temp of the incoming and outgoing
water in
the loop. I would increase the flow and drop the temp if it were me. This
can
be done with a higher horse motor and a fan with a higher flow rate of
air. The
pitch on the blades can increase the ccf. You'll need a different motor of
the
same rpm with at least a 1/15 hp.


What drugs and or thought of simple thermodynamics are you on?
You should stop trying to answer questions that you have no clue about. One
day, its gonna bite you on the ass.


candice

1/30 is a pretty small motor. You can either try and get a larger motor for
that one. Another thing that sometimes helps is to put a fan blowign towards
the heater. Circulate the newly heated air into the room.

Yes, I said "towards" the heater. Seems to work better than blowing from the
heater towards the room.

--

Christopher A. Young
Learn More about Jesus
www.lds.org
www.mormons.com


"Mark" wrote in message
...

Hoping someone can offer some guidance. I do want to state that I will not
be doing the work myself but will have a licensed electrician replace the
motor in my unit heater if it is a good option. I am asking here instead of
playing phone tag with the electrician and waiting two weeks for a call back
plus I know there are a lot of experienced folks here that can tell me if
I'm thinking in the right direction.


Here's the question:

I have a Reznor vertical hydronic unit heater model hh-175. It's currently
used for on-demand heating of a garage. The heater has a 1/30 hp motor that
turns at 1550 rpm's. Problem I'm having is that the heater puts out some
decent heat and raises the temp of the room but not quite enough to overcome
the drafts in the old building when it's really cold out. The hot water to
the heater is about 190 degrees which according the heater manual produces
about 60k btus at about 550 cfm. The hot water return on the heater is still
extremely hot so it appears that the heater does not deplete the heat from
the coils all that much. What I'd like to do is put a larger motor on it to
try and increase the cfm's to use more of the heat that appears to be
available. Doing the also may increase air circulation in the room to spread
the heat around a bit more also. Does this sound like a good or a bad idea
?

Thanks,

Mark

"CLSSM00X7" wrote in message
I like your idea. You should
have a ten degree difference in the temp of the incoming and outgoing
water in
the loop. I would increase the flow and drop the temp if it were me.
candice


Thanks for the information. I had not realized they changed the law of
physics and how they affect thermodynamics. I'll pick up a new book.
Ed

Thanks everyone for the informative answers. I do have another one of these
heaters that I can hook up but was hoping to take the cheap way out and
avoid chopping into the pipes since the system is all winterized.

Mark


"Mark" wrote in message
...

Hoping someone can offer some guidance. I do want to state that I will not
be doing the work myself but will have a licensed electrician replace the
motor in my unit heater if it is a good option. I am asking here instead
of
playing phone tag with the electrician and waiting two weeks for a call
back
plus I know there are a lot of experienced folks here that can tell me if
I'm thinking in the right direction.


Here's the question:

I have a Reznor vertical hydronic unit heater model hh-175. It's currently
used for on-demand heating of a garage. The heater has a 1/30 hp motor
that
turns at 1550 rpm's. Problem I'm having is that the heater puts out some
decent heat and raises the temp of the room but not quite enough to
overcome
the drafts in the old building when it's really cold out. The hot water to
the heater is about 190 degrees which according the heater manual produces
about 60k btus at about 550 cfm. The hot water return on the heater is
still
extremely hot so it appears that the heater does not deplete the heat from
the coils all that much. What I'd like to do is put a larger motor on it
to
try and increase the cfm's to use more of the heat that appears to be
available. Doing the also may increase air circulation in the room to
spread
the heat around a bit more also. Does this sound like a good or a bad
idea
?

Thanks,

Mark

Mark

Before you start hackin and whacking

One question

Are the fins on the coil clean...you never indicated how old or how long this
unit had been in service.

If the fan is running with your really low delta t between supply and return
and lack of heat from the heater; a good cleaning may be in order

Or it could be one of maybe 48,345 things
but have fun

Vic Plank
Lancaster PA

First snow of season tomorrow

Vic, It's actually a new unit heater, only been in use for about 2 weeks,
coil looks good and clean. The heater seems to push out a good amount of
heat but not quite enough to overcome the heat loss from the building..


Mark



"POPPYPLANK" wrote in message
...
Mark

Before you start hackin and whacking

One question

Are the fins on the coil clean...you never indicated how old or how long
this
unit had been in service.

If the fan is running with your really low delta t between supply and
return
and lack of heat from the heater; a good cleaning may be in order

Or it could be one of maybe 48,345 things
but have fun

Vic Plank
Lancaster PA

First snow of season tomorrow

Dollar_Jim wrote:
responding to
http://www.homeownershub.com/mainten...on-490410-.htm
Dollar_Jim wrote:
Mark has a great point.

Nope. Ed had a great point.

Putting a fan to distribute the heat defeats the
purpose of
hydronic heating system.

The heating unit that is the subject of the thread is a forced fan unit.
Without a fan you will get minimal heat from the unit.

Your post is useless - the latest idiot from homeowners hub. And it
responds to a thread that is over 7 years old. Where does homeowners hub
find people so stupid?

And you are not responding to a homeowners hub thread.
The thread is from a usenet newsgroup - alt.home.repair (and probably
another usenet newsgroup.)
Maybe you could find out what usenet is.

Homeowners' hub is a parasite that steals our work. It doesn't even
attribute the source.

If you don't want to figure out usenet, I suggest using google-groups.