Condensation Trap

[GMCAMARO]

I have a 120K BTU heater in my garage. The heater is a forced hot air system. I turn the heater off at night During the evening the the temperature drops to 0. It is cold. I ran a heat tape to the condensation trap. The trap would still freeze. I got frustrated and took the trap off, so now the two pipes one from the heat box and one from the cold air intake drain directly to the pipe the condensation trap drained too.

So far the the change has worked perfectly, I do not understand the trap. The trap does begin to drain until it is half full of water. What is the point to that trap why not just drain the way I have done? And what are the long term consequences of what I have done?

The btrap has frustrated me since new, the box always leaned towards the drain and yet it would constantly freeze.

 

[Sidekick]

The trap is in the system to keep air from displacing the water and keeping it stuck in the furnace or a/c. If you eliminate it , it is possible for water to back up into the equipment and overflow or stall the furnace.

The average person would think the opposite, but, it is not the case.

In the position of a furnace trap- it keeps monoxide from filling the space, and in an a/c where the air velocity is greater than heating, air WILL hold the water back when it seeks it's way to the drain.

 

[GMCAMARO]

The trap is in the system to keep air from displacing the water and keeping it stuck in the furnace or a/c. If you eliminate it , it is possible for water to back up into the equipment and overflow or stall the furnace.

The average person would think the opposite, but, it is not the case.

In the position of a furnace trap- it keeps monoxide from filling the space, and in an a/c where the air velocity is greater than heating, air WILL hold the water back when it seeks it's way to the drain.

Thank you.

The issue is that with the trap, it would back up and shut the system off.
Your explanation was excellent. Since water was backing up with the trap in place and with your explanation I believe my act of removing it was correct.

Thanks

 

[Sidekick]

you misunderstood me- the traps have to be in place as per equipment DESIGN, if the equipment is in an unconditioned space you need to provide a heat source for your equipment or the warranty is cancelled.


A 90 percent efficient furnace should never be installed in an unconditioned space without adequate provisions for heating the condensate. Otherwise the heat exchanger and the drain system in the equipment will fail and may KILL YOU!

Combustion gas should not be able to reach the drain- that is what the trap is for. There are airswitches that tie into your secondary heat exchanger if the sense a positive pressure- they will cause nuisance shut downs of your furnace. Don't think you are tricking your furnace to run right- you are setting yourself up for damage to your equipment and possible death from equipment failure.

 

[Sidekick]

Priming the Drain

Furnaces produce water through combustion, and the water has to be drained away from the furnace. In connecting this condensate drain, the furnace's drain trap has to be primed first. To do this pour a few cups of water down the furnace's vent pipe after installing the condensate vent. The condensate pump should be designed for furnace condensate needs.

Prevent Freezing

You should prevent the drain trap and the drain line from freezing since this will turn off the furnace. The water vapor is condensing in the vent pipe, and the vent pipe should be pitched back one-fourth of an inch for each foot of horizontal run in order to allow the condensate to run back to the condensate vent. This also helps prevent the formation of ice on the exit to the condensate vent.

Condensate Vent Specifications

The condensate PVC vent should be a minimum of 5 feet, with one elbow. It should not have any slackening in the piping that could fill with water and cause issues. The vent should be hung securely and should have support for every 5 feet it runs horizontally.

Drain Connections

Generally, condensing furnaces need two drain connections. One serves to carry water from the vent pipe to the trap. Another carries the water from a secondary heat exchanger to the trap. This depends on the manufacturer and the positioning of the venter motor.


Read more: Code Requirements for a Condensate PVC Vent for a Gas Furnace | eHow.com http://www.ehow.com/list_7729814_code-pvc-vent-gas-furnace.html#ixzz1iiM89S00

 

[Sidekick]

NOTE: These furnaces are designed for a minimum continuous
return-air temperature of 60°F or intermittent operation down to 55°F
such as when used with a night setback thermostat. Return-air
temperature must not exceed a maximum of 85°F. Failure to follow
these return-air temperature limits may affect reliability of heat
exchangers, motors, and controls.

The nimrod who sold you a 90 percent or better furnace for such low operating temps should have his license pulled.

 

[HVAC Phil]

NOTE: These furnaces are designed for a minimum continuous
return-air temperature of 60°F or intermittent operation down to 55°F
such as when used with a night setback thermostat. Return-air
temperature must not exceed a maximum of 85°F. Failure to follow
these return-air temperature limits may affect reliability of heat
exchangers, motors, and controls.

The nimrod who sold you a 90 percent or better furnace for such low operating temps should have his license pulled.

But anyone can install these, all they have to do is go online! Who cares if it's right, better than paying to do it correctly. Just like all the garage heater failures posted on the board, improper installation. I've never had a failure with them, ever.

 

[Sidekick]

But anyone can install these, all they have to do is go online! Who cares if it's right, better than paying to do it correctly. Just like all the garage heater failures posted on the board, improper installation. I've never had a failure with them, ever.

Here in Northern Michigan it gets quite cold and the traps inducer motors and other plastic parts fail if allowed to get too cold. The manufacturers did not build these for sale to low temperature installations for a reason- they fail. The heat exchanger parts do not hold up well to wide shifts in temperatures. The inside plates tell you th max and minimum temperatures so you do not get killed or you house burn down because you operated them too hot. And if you run them too cold = you do not get exchanger failure and get killed.

I am all for the homeowner to instal their own equipment- if they follow the guidelines.

 

[GMCAMARO]

NOTE: These furnaces are designed for a minimum continuous
return-air temperature of 60°F or intermittent operation down to 55°F
such as when used with a night setback thermostat. Return-air
temperature must not exceed a maximum of 85°F. Failure to follow
these return-air temperature limits may affect reliability of heat
exchangers, motors, and controls.

The nimrod who sold you a 90 percent or better furnace for such low operating temps should have his license pulled.

What would you recommend a proper heater in a detached 1800 sq foot 3 bay garage in Massachusetts be?

The garage is fully insulated and used year round.

Propane is available and already installed.

 

[Sidekick]

A hot Dawg, they are reliable and designed to work in garages. The are made to handle extremes in temperature changes.

 

[rlitman]

They're saying not to turn the heater off at night, and just set the temperature back.

 

[Sidekick]

They're saying not to turn the heater off at night, and just set the temperature back.

90 percent efficient furnaces are not designed to operate below 30 degrees inside temperatures. The manufacturers do not recommend installing these in Cottages for intermittent use or garages where they will start at temps below 30.

 

[HVAC Phil]

I have a 2 stage 90% furnace in my garage with a/c. I keep my garage at 60. It is installed in the attic, insulated room built around it. It stays 65 in the room.

 

[Sidekick]

I have a 2 stage 90% furnace in my garage with a/c. I keep my garage at 60. It is installed in the attic, insulated room built around it. It stays 65 in the room.

You did what the manufacturer advised. I give you 50 brownie points

 

[HVAC Phil]

You did what the manufacturer advised. I give you 50 brownie points

I would an HVAC contractor would install it right....but you never know with some hacks out there!