Commissioning: Boiler tips (part 1 of 2)

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

Air removal from the system

Glow Brand · C95 & C140

The boiler's two automatic air vents only purge the boiler itself. They do not clear the system plumbing. Additional air vents and bleeders must be placed around the system, ideally higher up and in areas with guaranteed positive pressure, such as near the fill point and expansion tank.

1. Install air vents and bleeders across the system, not just at the boiler.
2. Place air removal devices high in the system and near the fill and expansion tank.
3. Do not install flow checks, motorized valves, or shutoff devices between the closely spaced tees and the expansion tank, except for servicing.

Altitude rating of the boiler

Glow Brand · C95 & C140

The unit ships set for 0 to 4,500 ft. Use the sea-level input rate for installs from 0 to 2,000 ft. Above 4,500 ft the factory must be contacted for a high-altitude setup.

1. Confirm the install altitude before setting the input rate.
2. Use the sea-level input rate for 0 to 2,000 ft.
3. Contact the manufacturer for installs above 4,500 ft.

Boiler sizing for the heating system

Glow Brand · C95 & C140

Size the boiler with an accepted method. Use the AHRI I=B=R Guide for convection radiation. Use the radiant tubing maker's guidance for new radiant systems. If an indirect water heater is used, the boiler must meet that heater maker's output requirement.

1. For baseboard or radiators, size with the I=B=R Guide RHH.
2. For new radiant systems, use the tubing manufacturer's boiler sizing guide.
3. With an indirect water heater, confirm the boiler output meets the heater manufacturer's requirement.
4. Check that maximum combustion air and exhaust pipe lengths in Section 4 are not exceeded.

Check combustion above 2000 ft

Glow Brand · C95 & C140

Above 2000 ft the boiler's combustion must be checked with a calibrated combustion analyzer. The installer is responsible for checking and adjusting combustion for safe operation.

1. Use a calibrated combustion analyzer at elevations above 2000 ft.
2. Adjust combustion as the manual directs, then record the results.
3. The manual points to Section 9.0 for this adjustment, which does not match the section list; confirm the correct procedure in the gas valve setup section.

Combi boiler commissioning checklist

Glow Brand · C95 & C140 combi boiler commissioning

Work through this checklist on the commissioning sheet before handing the boiler over. Record readings and the procedure results, then sign and date the sheet.

1. Confirm hydro, gas and water are available at the appliance before starting.
2. Confirm the unit matches the work order and that model and serial numbers are recorded.
3. Check that there is no flammable material or liquid near the appliance.
4. Keep a minimum 24 in. clearance in front of the appliance.
5. Check voltage and polarity.
6. Check that all gas and water connections are tight and leak free.
7. Check gas pressure at the appliance and record it.
8. Check CO2 against the installation manual values and record it.
9. Record the CO reading in ppm.
10. Check that the venting meets the installation manual and local codes.
11. Check that the condensate trap is primed and not blocked.
12. Check that the drain tube and condensate hose are installed correctly.
13. Check that both automatic air vents are open.
14. Bleed air from the heating loop or recirculation line if fitted.
15. Burp the circulation pump inside the combi.
16. Confirm parameters are set to suit the appliance.
17. Check that the safety components work as intended.
18. Check that the pressure relief valve is installed correctly and operating.
19. Leave the installation manual with the appliance.
20. Enter the contractor, technician and homeowner details, sign the sheet and record the date.

Confirm gas type before startup

Glow Brand · C95 & C140

The boiler leaves the factory set for one gas type shown on the rating plate. It cannot be converted to another gas, and no natural gas to LP conversion kit is available.

1. Check that the gas type on site matches the rating plate.
2. Do not attempt a natural gas to LP conversion, since no kit exists.
3. Use the wrong gas and the burner can run dangerously.

DHW flow and capacity limits

Glow Brand · Instantaneous DHW

Instantaneous DHW has no storage. Output temperature falls off as flow rises past the boiler's heating capacity. A storage tank can be added for large draws.

1. Confirm the flow rate at the fixture stays within the boiler's heating capacity.
2. Use the combination inlet screen and flow restrictor cartridge; do not run without the screen.
3. Use a DHW storage tank per the schematic in Section 7.3 when large draws are needed.

DHW flow limiter and pressure drop

Glow Brand · C95 & C140

Each model ships with a DHW flow limiter, and the pressure drop vs. flow curves show its effect. The curve values are not readable on the printed page.

1. C95: use the 2.4 gpm flow limiter and check against the C95 DHW pressure drop curve.
2. C140: use the 4.0 gpm flow limiter and check against the C140 DHW pressure drop curve.
3. To reach higher DHW flow, change the flow restrictor (see section 14.7).

Gas supply and piping cautions

Glow Brand · Gas piping

Keep piping stress off the gas valve, use a sediment trap on vertical runs, and use a manual shut-off upstream of any flexible connector.

1. Use a manual gas shut-off valve upstream of the flexible connector.
2. Support piping so no load is put on the internal gas valve.
3. Install a sediment trap at the inlet to the boiler if the gas line runs vertically.
4. Use thread compound that resists natural gas, applied from two threads back from the end.
5. Do not purge gas through the boiler's internal fittings; loosen only the line connections outside the unit.

Gas type cannot be changed in the field

Glow Brand · C95 & C140

The boiler is factory set for the gas type on the rating plate and must not be converted to another gas.

1. Check the rating plate gas type before installation.
2. Do not convert the boiler to a different gas.

Head available for the heating loop (worked example)

Glow Brand · C95 & C140

Use the pump curve and heat exchanger pressure drop to find the head left for the field piping and heating devices, using a 5 gpm target flow on the C95.

1. Read the pump head at the target flow. Example: 25.5 ft at 5 gpm (Fig. 2.3).
2. Read the heat exchanger pressure drop at the same flow. Example: 4.4 psi (10.2 ft) at 5 gpm (Fig. 2.4).
3. Subtract the pressure drop from the pump head. Example: 25.5 - 10.2 = 15.3 ft left for piping and heating devices.
4. On the C140, the factory low loss header is supplied for field installation, so the field-supplied secondary CH pump provides the external head.

Leak check the vent on first startup

Glow Brand · C95 and C140 at commissioning

All exhaust venting connections must be checked for leaks with soap solution at first startup. Repair any leak before running the unit.

1. Apply soap solution to every exhaust vent connection at startup.
2. Repair any leak before continuing operation.

Leak testing and gas pressure test cautions

Glow Brand · Gas piping

Isolate the boiler from the gas line for any test at 1/2 PSI (14 in. w.c.) or more, and never use an open flame to find leaks.

1. Close the boiler's individual manual shut-off valve during supply system pressure tests at or below 1/2 PSI.
2. Disconnect or isolate the boiler if the test pressure will be higher than 1/2 PSI.
3. Use a gas leak detector or soapy water on all fittings and retighten any bubbling connections.

Minimum flow and overheating risk

Glow Brand · C95 & C140

The low mass heat exchanger needs a minimum water flow whenever the burner is on. Too little flow lowers efficiency and can cause overheating, premature failure, and void the warranty. Running with insufficient water level also causes overheating.

1. Confirm the minimum flow rate through the boiler whenever the burner runs.
2. Do not run the boiler without sufficient water level.

Pressure relief assembly and low loss header

Glow Brand · C95 & C140

The C95 comes with a pressure relief assembly that needs 3 inches of clearance from gas and piping. The C140 must use the factory low loss header. The header is optional for the C95. Without it, a primary/secondary tee arrangement is needed to keep minimum flow (not required on C95).

1. Keep 3 inches of clearance from gas and piping around the relief assembly.
2. On C140, install the low loss header. Do not omit it.
3. On C95, the low loss header is optional; use primary/secondary tees if it is not fitted.

Pressure relief valve installation

Glow Brand · C95 & C140

The relief valve must be vertical at the boiler outlet, on the CH return fitting. Its drain must exit horizontally from the side and elbow down. Pipe the discharge to a location where steam or water will not cause damage or injury.

1. Mount the relief valve vertically at the boiler outlet.
2. Point the drain outlet sideways, then elbow it down.
3. Pipe the discharge to a safe location.

Prime the condensate trap before startup

Glow Brand · Condensate trap priming

The trap must hold water before the boiler starts, or flue gases can enter the building.

1. Remove the flue gas inlet plug (T).
2. Fill the trap (S) about three quarters full with water.
3. Replace the flue gas inlet plug (T).
4. Check the trap is secure and not under strain.

Set DHW temperature low to limit scald risk

Glow Brand · C95 & C140

Set the domestic hot water to the lowest temperature that still meets the user's needs. The manual recommends 120°F/49°C, which lowers scald risk and also improves efficiency and reduces scale.

1. Set the DHW temperature to 120°F/49°C or lower where possible.
2. Fit a tempering (mixing) valve in the domestic hot water supply to cut point-of-use temperature.
3. Keep DHW at or below 140°F/60°C. The manual says the warranty is void above this setting.

Set the appliance type for CPVC / high temperature venting

Glow Brand · B85, B120, B160 (NG and LP)

Factory setting limits flue temperature to 149 F for PVC. For CH or DHW setpoints above 140 F the vent must be CPVC and the control must be told.

1. Set 2.138 to 52 (B85/B120 NG), 53 (B160) or 55 (B85/B120 LP) for a 194 F flue limit; 50, 51 and 54 are the PVC defaults.
2. Raise 2.024 (max CH setpoint) and 2.003, and for DHW 2.091 and 2.115, to the required values up to 180 F.
3. Exceeding what the vent allows gives Loc 16.

Verify carbon monoxide alarm before operation

Glow Brand · C95 & C140

The installer must confirm that at least one carbon monoxide alarm is installed in the living space before the appliance is put into operation.

1. Confirm a CO alarm is installed in the residential living space.
2. Install the alarm per the alarm maker's instructions and local code before energizing the boiler.

Water hardness and DHW cleaning

Glow Brand · DHW heat exchanger

Water above 50 ppm calcium carbonate must be softened. Brazed plate DHW exchanger can be acid cleaned if scaled.

1. Install a water softener if hardness is above 50 ppm calcium carbonate.
2. Clean the brazed plate exchanger with 5% phosphoric acid, or 5% oxalic acid if cleaned often.
3. Pump cleaning solution at a minimum of 1.5 times normal flow, preferably back-flushed.
4. Rinse with clean water, then flush with 1-2% sodium hydroxide or sodium bicarbonate solution before a final rinse.

Cascade set-up

HTP · EL-80, EL-110, EL-150, EL-220, EL-299, EL-399 (N/LP)

Address boilers for a cascade.

1. Master: function 15 = 0, function 23 = 926 Boiler
2. Followers: function 15 = 1, 2, ... (no duplicates), function 23 = 926 Boiler
3. A follower with an indirect tank must be address 2 or higher
4. Master and follower set points must match
5. Daisy-chain CAT3/CAT5 cables, max 200 ft

Check thermostat circuit for stray voltage

HTP · EL-80, EL-110, EL-150, EL-220, EL-299, EL-399 (N/LP)

Common wiring fault with zone valves.

1. Disconnect the two thermostat wires from the boiler
2. Meter across them with thermostats and zone valves closed one at a time
3. There must be no voltage
4. Fix external wiring if any voltage shows

Start-up combustion and gas checks

HTP · EL-80, EL-110, EL-150, EL-220, EL-299, EL-399 (N/LP)

Items to record at light-off.

1. Static and light-off drop gas pressure (3.5 to 14 in. w.c., max 1 in. drop)
2. Flame current at high and low fire
3. CO2 and CO at high and low fire against the combustion table
4. Fill condensate trap with water before first start
5. Pressurize 12 to 15 psi

Set up a cascade (assign sub unit IDs)

Navien · Navien NHB-H condensing boilers: NHB-150H, NHB-110H, NHB-080H, NHB-055H

The main boiler assigns IDs 1-16 to the sub boilers; only the main unit's settings are used. The Start function is available on NHB-110H/150H only.

1. Hold Back and Menu together for 3 seconds on the main unit.
2. Open 4. Cascade Status and Settings.
3. Choose 1. Cascade System Setting and start it so the main assigns IDs to the subs.

Canadian vent installation requirements

NTI · Installations in Canada

Additional requirements for Canadian installations.

1. Use a vent pipe system certified to ULC-S636.
2. Keep the first 3 feet of vent pipe from the boiler flue outlet readily accessible for visual inspection.
3. Do not mix components from other vent systems or unlisted pipe or fittings.
4. Use double-wall or insulated intake pipe in cold climates to stop moisture condensing in the incoming air.

Combustion check at elevation above 2000 ft

NTI · TRX boilers above 2000 ft

Above 2000 ft, the installer must check and adjust combustion with a calibrated combustion analyzer. Derate the capacity as the high elevation table shows.

1. Check combustion with a calibrated analyzer.
2. Adjust combustion per the manual.
3. Apply the required capacity de-rate for the elevation.

Combustion check procedure

NTI · Trinity Tft60, Tft85, Tft110, Tft155, Tft175, Tft200, Tft250, Tft300, Tft399

Set-up of CO2 and CO after start-up or propane conversion.

1. Run the boiler at maximum fan speed and hold gas line pressure inside the allowed range
2. Read CO2 and CO and adjust the throttle screw until both are inside the limits
3. Drop to minimum fan speed and confirm combustion is still smooth and in range; if not, stop and call NTI

Do not fire the boiler before filling

NTI · NTI TRX150 startup

The boiler must not be operated until all connections are complete and the heat exchanger is full of water. Firing it dry will damage the boiler and void the warranty.

1. Complete all water and gas connections.
2. Fill the heat exchanger with water.
3. Only then power on and operate the boiler.

Dry run of the ignition sequence on new plastic vent

NTI · Trinity Tft60, Tft85, Tft110, Tft155, Tft175, Tft200, Tft250, Tft300, Tft399

Needed when the vent cement has had less than 8 hours to cure.

1. With power off, glue the vent and air intake and keep the gas valve shut
2. Pull the cable off the spark ignition transformer (keep 2 in from the spark circuit)
3. Power up and make a heat call
4. Let the control run three full ignition trials with pre-purge and post-purge until it locks out; repeat twice more for nine in total
5. Power off and reconnect the spark cable