Rapid Temperature Rise Advisory 6

Heatmaker – Heating-Only Type Boilers, such as Models H, EDP (Endurance), CB, and HWG (9600 Series) and Summit Boilers

Heatmaker.com is committed to providing you with information that can help you avoid mechanical malfunction before it becomes an issue.

Function:

This series has no built-in storage tank and requires a flow-limiting thermostat as its flow (supply). This limits the minimum temperature of the boiler to 150-160 degrees F and prevents the cold system return from creating condensation on the copper fin coils that would eventually foul them.

Note: Make sure that the boiler pump has been checked and is functioning properly.

Thermostat Locations:

• H and EDP models have an automotive type thermostat located in a black ips-type union installed in the supply-to-system piping no more that 2 feet from the boiler
• The 9600 series and Summits have a built-in thermostat accessible via a removable plate on the top jacket.

Typical Problems:

In normal operation upon ignition, boiler temp rises quickly to 150 to 160 degrees F and then settles there until the return temperature starts to rise.

Failures:

• Type A:  The thermostat is stuck in the open position. The temperature rise upon ignition is very slow until returns start to heat-up.
• Type B:  The thermostat fails to open. The temperature rises rapidly and the unit shuts down on its limit.

Replacement Thermostat Part Numbers:

Models H and EDP:  2400-030

Models CB and HWG, pre-1995:     2400-129

Models CB, HWG and Summit, post-1995:  2400-130

If you have any questions, call Heatmaker’s technicians Monday-Friday, 5:00 a.m. – 7:00 p.m., EST; and Saturday 5:00 a.m. – 1:00 p.m., EST.

Heatmaker.com

Extensive Inventory.  Immediate Shipping.

781-961-166

Lockouts Advisory 2

Combustion Lockouts on Heatmaker H/HW Plus & Mark II Units

Heatmaker is committed to providing you with information that can help you avoid mechanical malfunction before it becomes an issue. This describes lockout modes for the Heatmaker H/HW Plus units and for the Heatmaker Mark II units.

Lockouts are a critical safety feature that mitigates the possibility of a faulty start-up when the flame-sensing device fails to identify combustion within 5 to 7 seconds of gas valve opening or during the combustion cycle. The unit will attempt 3 cycles before going into lockout.

When the unit is in lockout mode, the internal pump will run continuously and its temperature, as seen on the temperature gauge, will drop below 160 degrees. The unit will reset by interrupting its power switch or a red 24-volt wire in control circuit.

There are three different failure modes leading to lockouts and, therefore, it is important to identify in seconds the length of time that the gas valve is powered. The length of the cycle will be either (a) 1 to 2 seconds, (b) 5 to 7 seconds, or (c) more than 10 seconds.

Failure Modes and Evaluation:
(a) 1–2 seconds. Power that is drawn by when the gas valve powers-on drops the 24 volts below the module’s minimum.
1. Many Mk-II units have a small tapered minimum pressure switch (2 red wires) which may leak causing it to ground out the 24-volt circuit. Remove two red wires and temporally jump to test operation.
2. Gas valve grounded or shorted: Read resistance across valve connections, with orange wire removed. Resistance should be 14 to 16 ohms.

(b) 5-7 seconds. The unit fails to identify strong flame signal.
1. Faulty Igniter. Read resistance across igniter, should be under 100 ohms(60-80 cold).
2. Confirm gas source is present either by observing that other commonly connected gas appliances are working or using water gauge at inlet of valve. (4” to 14” water column). [Do not attempt to measure gas pressure at valve outlet, as this is a negative pressure gas valve.]

(c) 10-plus seconds. The unit establishes flame but then fails after 10 seconds or longer.
This applies to concentric type venting (pipe 3” within a pipe 5” venting) through wall venting. Exhaust gases in the 3”inner pipe are leaking through connection joints into outer 5” air source pipe. These gases dilute air source and cause flame failure.
1. Typical identification is strong unpleasant smell at exhaust terminal.
2. Remove and repair (seal) the leaking joints) or replace venting with factory approved stainless vent piping.

If you have any questions, call Heatmaker’s technicians Monday-Friday, 5:00 a.m. – 7:00 p.m., EST; and Saturday 5:00 a.m. – 1:00 p.m., EST.

Heatmaker.com
Extensive Inventory. Immediate Shipping.
781-961-1660

LowLimit Advisory 1

Heatmaker Model HW Units – Low Limit Control

Heatmaker is committed to providing you with information that can help you avoid mechanical malfunction before it becomes an issue.

These service issues relate to Low Limit control and its function.

The Low Limit control has two functions. First, it maintains minimum tank temperature for instant hot water use. Second, it provides domestic hot water (DHW) priority by temporarily cutting the 24-volt power on the thermostat (T-T) terminals during a domestic hot water draw.

Problems may result from improper positioning, venting or wiring; each allowing the unit to operate for domestic hot water but not enabling heating zones to operate.

If you are experiencing problems:

1. Check to be sure that the Low Limit is properly mounted on the vertical section of the ¾” hot water supply coming out of the tank, close to the tank.
2. If the positioning is correct and space heating still does not function, then release any air via the vent screw on top of DHW tank.
3. Finally, check the wiring to ensure that it is correct.

Wiring sequence (wiring color of Low Limit connects to wiring color of unit):

HW+ (Plus)

Red (on Low Limit) to Red (on unit), Black to Gray, Brown to White

HW – M2 (Mark II)

Red to White/red stripe, Brown to Gray, Black to Red/Black stripe

If you have any questions, call Heatmaker’s technicians Monday-Friday, 5:00 a.m. – 7:00 p.m., EST; and Saturday 5:00 a.m. – 1:00 p.m., EST.

Heatmaker.com

Extensive Inventory. Immediate Shipping.

781/961-1660