LAARS Mighty Therm2 MT2P (Sizes 500–2000 MBTU/h) - Install and Operating Manual - Manual (Page 23)

MT2P Pool Heater Page 23
sections by lifting up. On the larger appliances, a
center heat exchanger support must be unbolted
before it can be removed.
7. Remove the heat exchanger from the unit. Note:
The heat exchangers are heavy and will require
two people to remove to avoid personal injury.
8. Clean the heat exchanger: A light accumulation
of soot or corrosion on the outside of the heat
exchanger can be easily removed. Use a wire
brush to remove loose soot and scale from the heat
exchanger. Do not use water or compressed air for
cleaning.
9. NOTE: While the heat exchanger is out of the
unit, inspect the firewall refractory insulation.
Replace if necessary.
10. Inspect the inside of the copper tubes for scale
buildup. Scale can build up on the inner surface of
the heat exchanger tubes, which can restrict water
flow. If the tubes show signs of scaling, clean the
internal surface. Laars offers a tube cleaning kit
(p/n R0010000).
11. Reassemble in the reverse order, and check
appliance operation after start-up.
NOTe: The Warranty does not cover damage
caused by lack of required maintenance, lack of
water flow, or improper operating practices.
unit operates properly, by following the set-up procedure
in this manual. Use caution in handling the blower,
ensuring you do not put pressure on the blower wheel.
7.2.12 Flow Switch
The MT2P uses a paddle-type flow switch to
ensure that the unit has water flow before ignition is
allowed.
7.2.13 Heat Exchanger Coil
Caution
Black carbon soot buildup on a dirty heat exchanger
can be ignited by a random spark or flame. To
prevent this from happening, dampen the soot
deposits with a wet brush or fine water spray before
servicing the heat exchanger.
The MT2P has a pre-mixed burner system. These
systems provide the burners with sufficient air for
complete combustion, and black carbon sooting is
seldom experienced. If sooting is suspected, view ports
for inspection of the heat exchanger are provided on
both sides of the heater. They are located below the
headers, and are accessed by opening the small round
cover that is attached by one screw. In the unlikely
event that there is a buildup of black carbon soot
or other debris on the heat exchanger, clean per the
following:
1. Disconnect the electrical supply to the unit.
2. Turn off the gas supply by closing the manual gas
valve on the heater.
3. Disconnect and remove the wires, conduit and
sensors from all components that are attached to
the inlet/outlet header.
4. Isolate the heat exchanger from the water supply.
5. Disconnect the header flanges from the inlet and
outlet.
6. Allow the heat exchanger to drain. Remove
the front cover(s). Remove the venting and
remove the top, by removing the screws that
attach the top to the side panels. Remove the
side panels. Remove the front lower panels
sealing the combustion area. To remove the gas
train, disconnect the unions located above the
intermediate pan and the field installed union
located outside the cabinet, and pull up, bringing
the union end connectors through the grommets in
the intermediate pan. To remove the intermediate
pan, remove the slide out control assembly and
blower(s) to reveal the screws. Remove the
screws holding the intermediate pan, and lift up to
remove it. The heat exchanger has integral metal
sections attached, which connect to the frame of
the boiler. Locate and remove the screws along
the front, rear and bottom of the integral metal
sections, and remove the heat exchanger and metal