Our MGTA 07 EMAES Dayton gas furnace has a crack in the condensate pump. Where can we find a replacement?

Help in the link, but you LPG Gas fitter should know all this. All gas installations must be done by a gas certified technician.

https://www.google.com/search?q=Dayton+Furnace+3E847+LPG+Pilot+orifice+size

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There are several questions that need to be answered about what type of system you have, but i found this posting that may help:
As your gas furnace runs, is there water leaking at the base? Is the furnace's air filter wet, too?There are a few things that could be happening here. But if you have a high-efficiency furnace, here's the most common cause: a condensation leak.
We'll explain why a furnace creates condensation, and what's causing it to leak out of your furnace.
Note: You'll know if you have a high-efficiency furnace if:

• The yellow energy guide tag says your furnace's efficiency is 90% or higher AFUE.
• The vent/flue pipe is white PVC as opposed to metal.

Why a high-efficiency furnace creates condensation
How in the heck does a high efficiency furnace create condensation/water anyway?
It's all about how the furnace extracts heat from combustion gases.
A lower-efficiency furnace extracts some heat from combustion gases and then quickly vents them out the flue pipe.
But a high-efficiency furnace, to extract more heat, has 2 heat exchangers. These allow the furnace to extract heat from the gases for a longer period of time. This causes the combustion gases to cool and then condense.
That condensation then exits out your home through a drain. But if that water is pooling around the furnace, there's a problem preventing it from draining properly.
Causes of a condensation leak around a high-efficiency furnace

• Clogged condensation tubing
• Clogged condensation drain
• Breaks in the condensation line
• Issues with the condensate pump (if you have one)

You'll need a furnace technician to diagnose which of these is the issue and then fix it.
Other causes of leaking water around a furnace
If you have a conventional, standard-efficiency furnace...then its flue pipe may be incorrectly sized.
If you have a whole-house humidifier connected to the furnace...there may be an issue which is causing the humidifier to leak into your furnace. Your humidifier should be getting annual maintenance from a professional to prevent this.

Do not run contentiously during heat mode. the fan runs at a slower speed with heat and heat fires first then the fan cycles on during heat cycle then when heat satisfies the thermostat the heat will cycle off and fan will run for a couple more minutes and then cycle off. So set stat on fan cycle to auto.

Check heat exchanger for cracks or holes which will cause the fan to blow out the flames. The flame sensor on the pilot or burners has to be in constant contact with flame to operate normally. If the flame is put out by a cracked exchanger the exchanger or furnace needs to be replaced.

Please have this checked out by a technician. If there is a crack in the heat exchanger it could do just as you described. The blower blows air into the combustion chamber and blows out the burners.

Hello,They probably make a universal one that can replace the factory one.The number off the old part itself is needed to cross reference the match.

safety problem yes fumes coming in to the house via heating vents , age ? but best bet is a new heater , go for new as it the long run it will be cheaper

If you dont see one the you,re suppose to have one before the fan . This is your first line if defense. from air borne pathogenes..

not hard but before replacing check pilot light and thermocouple for proper function and setting if pilot light not in right position thermocouple wont open gas valve if electronic ignition check for power and proper gap on igniter also check stat for proper function

When your furnace starts...the Ventor motor(exhaust fan) starts up....within a short time (seconds) the Pressure switch closes proving that the Fan is indeed running and the vent is not blocked...if this doesnt happen the furnace will not poweer the ignitor or fire at all....Check the vent pipe outside and look for obstructions or dirt on the screen inside the pipe...the condensate from the fuirnace may not be draining at all...due to plugged condensate drain lines...find this tube coming out of the furnace front...bottom of upper compartment usually , and pull it off the tap....if water starts coming out then your drain is plugged downstream of the furnace.