Other: General tips (part 2 of 2)

Short, practical technician tips on other for general. Check each one against the manual for your exact model before acting.

Trace a water-circuit blockage

Generic

Crack the inlet valve, open joints one at a time downstream with a bucket until flow stops — that's the restriction (valve vs condenser vs drain).

TXV/TEV, AXV/AEV, EEV/EXV naming (Pro Tip)

Generic

Same valves, different field abbreviations. Metering orifices are also called pistons, flowraters, flow restrictors, accuraters.

Undersized heating plant

Generic

Can overheat stack/chimney (fire); oversized wastes energy. Use outside dimensions for wall area (conservative).

UV lamps in walk-ins

Generic

Turn UV germicidal lamps off when anyone works in the box, or protect skin/eyes.

UV safety & placement

Generic

Never look at lit lamps; access doors need interlock; mount in return upstream of air handler or over/inside the coil and drain pan; check manufacturer location; sealed lamps contain mercury. Clean with window cleaner on a cloth, never touch glass; cool 15 min first.

Vane anemometer technique

Generic

Hold propeller at right angle to flow, let it stabilize ~1 min before recording.

Vapor barrier on warm side

Generic

Peeling paint near kitchens/baths = missing vapour barrier.

Vaulted ceilings

Generic

Add the triangular gable wall area. ACCA lists different values for 9'/10' ceilings.

Water hammer fix

Generic

Single thump when a water valve closes: add a tee with a short vertical dead-leg (air cushion) just upstream of the valve, or an expansion tank.

Water-cooled condenser short cycles on HP switch

Generic

If water stops, head rises, HP switch opens, pressure falls, restarts — the switch is the symptom; restore water flow. Post signs on hand valves. Rubber hose sections isolate vibration from building plumbing.

Zone panel discharge air sensor / outdoor reset

Generic

Newer codes require outdoor sensor so staging follows true load.

Zone panels have no serviceable parts

Generic

; tiny terminals — watch for loose strands/jumpers.

Closet and alcove ventilation

NTI · TRX150, TRX199, TRX199C

A boiler area under 150 cubic feet needs two ventilation openings. A boiler area of 150 cubic feet or more does not need them.

1. Size each opening at 1 sq in. per 1,000 BTU/hr, with a minimum of 100 sq in.
2. Place the lower opening within 6 in. of the floor.
3. Place the upper opening 6 in. from the top of the space.
4. In closets, do not use PVC vent pipe; use approved CPVC, polypropylene or stainless steel.

Cold storage handling

NTI · TRX150, TRX199, TRX199C

A boiler stored below 0 F must be handled carefully until its components reach room temperature.

1. Let the boiler reach room temperature before handling or installing it.

Condensate handling

NTI · TRX150, TRX199, TRX199C

The boiler produces condensate that must be neutralized before it goes to the drain. Freezing can block the trap and drain lines.

1. Neutralize condensate before it enters the drainage system.
2. Keep the condensate trap and drain lines protected from sustained freezing.
3. Make sure the boiler is level so condensate flows to the collection system.

Confined vs unconfined indoor combustion air

NTI · TRX150, TRX199, TRX199C

Space under 50 cubic feet per 1,000 BTU/hr of total input is confined. Space above that is unconfined.

1. Calculate total input of all fuel-burning appliances in the space.
2. If the space is confined, provide two permanent openings: one 6 in. below the ceiling and one 6 in. above the floor.
3. Size each opening at 1 sq in. per 1,000 BTU/hr, with a minimum of 100 sq in.
4. In a tight building, take combustion air from outdoors using the venting section.

Garage installation height

NTI · TRX150, TRX199, TRX199C

In a residential garage the burner and ignition devices must be kept well off the floor and protected from vehicles.

1. Mount the bottom of the boiler at least 18 in. above the garage floor.
2. Locate or protect the boiler so a moving vehicle cannot damage it.
3. Check local AHJ requirements before installing in a garage or closet.

Installation location limits

NTI · TRX150, TRX199, TRX199C

The boiler is indoor only and must be installed upright. Ambient must stay between 32 F and 104 F, and must not sit below 45 F for long periods because the fan can condense.

1. Install indoors only and upright in the vertical position.
2. Keep ambient between 32 F and 104 F.
3. Avoid prolonged exposure below 45 F to prevent fan condensation.
4. Keep at least 1 in. clearance around hot water and exhaust pipes.
5. Do not close existing ventilation openings.

Piping materials and sizes

NTI · TRX150, TRX199, TRX199C

Material and size limits for the water piping.

1. Use copper, brass, stainless steel, or black iron (CH loop only) fittings.
2. Do not use galvanized steel fittings in any loop.
3. Do not use dielectric unions on the DHW loop of a combi boiler. This voids the warranty.
4. Use at least 3/4 in. for DHW piping. Use 1-1/4 in. for CH piping (page 27). Page 31 lists 1 in. CH minimum, so check local code and the manual's minimum before sizing.
5. Use two wrenches when tightening water piping at the boiler.