Frequently Asked Questions

Find swift and convenient answers in our collection of go-to resources for troubleshooting and technical support.

What certification standards does Thermolec comply to? +

Thermolec is certified under CSA, CSA/US and UL standards. We also carry H-Stamp and National Board certifications for our electric boilers.

What are the minimum recommended air flow values for open and tubular/sheathed elements? +

It is recommended that the minimum air flow across the elements is 300 FPM (1.52 L/S) for open element heaters and 500 FPM (2.53 L/S) for tubular/sheathed elements.

What is the pressure drop across open and tubular/sheathed elements? +

The pressure drop can be estimated by referring to the Pressure Drop Chart included in the technical notes document on our website. These values are under the guideline that the depth of the element frame is 10” (254mm).

Can any thermostat be used with Thermolec heaters? +

Thermolec can provide thermostats with any given heater upon request. If a different thermostat is to be used, make sure that the output capabilities of the thermostat is compatible with what was ordered. • Active 0-10VDC signal for modulating heaters (Similar to Thermolec’s CTH-291) • Passive Thermistor output for modulating heaters (Similar to Thermolec’s DT-1040 and RT-1030) • Active 24VAC output for staged ON/OFF heaters (Similar to Thermolec’s CTH-010 or CTH-294) • Standard dry-contact thermostats for staged ON/OFF heaters.

What is an electronic air flow sensor? +

The electronic air flow sensor was designed specifically for VAV and CAV applications where the air flow may be too low, even below the recommended air flow. This is to be used in collaboration with modulating controls.

Can any temperature or air flow sensor be used for Thermolec heaters? +

No, only an NTC Type 3 Thermistor with a 10kΩ reading can be used with Thermolec heaters.

What is a PDS? Can the PDS be bypassed? +

The PDS (Pressure Differential Switch) is a safety device used to enable/disable the heater’s operation when sufficient air flow is achieved. It closes when there is a minimum of 0.05” of static pressure. It is forbidden to bypass the PDS if it appears to be malfunctioning during operation. A chattering PDS means there are air flow issues in the application that require attention.

Can the 24VAC on the transformer in the Thermolec heater be tapped to supply power to an external source (i.e. thermostat)? +

Yes, this can be achieved on the secondary side of the transformer. The HOT (24VAC) is usually indicated by red wiring, and the Ground (Common) is usually indicated by green wiring. We do not recommend, however, that the pull from the transformer exceed 10VA. This can cause premature failure of the transformer. It is best to inform Thermolec to size the transformer properly if it is known fact the transformer will used to power other sources.

What is FLA, MCA, and MOP/MOCP? +

These are terms to describe amperage values for a heater. FLA stands for “Full-Load Amps”, the maximum nominal current of a heater. MCA stands for “Minimum Circuit Ampacity”, a calculated value with a safety factor that specifies the minimum main power supply and wires. MOP/MOCP stands for “Maximum Overcurrent Protection”, the highest current rating that an electrical equipment's over-current protection devices (such fuses or circuit breakers) are permitted to handle. Note: MOP/MOCP values are not given by Thermolec. These values are to be determined by the installing electrician as per local Electrical Codes.

How does a voltage spike or drop affect the heater? +

A spike or drop in the voltage of an electric heater will vary both the capacity (kW) and amp draw of the heater. Since an electric heater is a resistive load, and the element resistance is a fixed value, an increase in voltage will increase both the capacity and amp draw, and a drop in voltage will do the opposite for both.

Can a different voltage be applied to a heater already designed for a set voltage? +

Although it is not recommended to apply a different voltage to a heater already designed for a set voltage, it can be acceptable to do so if the new voltage being applied is lower than the already-designed voltage. This will just result in a lower capacity and amp draw. It is not acceptable to apply a higher voltage that the already-designed voltage. Doing this will increase the capacity and amp draw of the heater, which can cause damage to the elements and components, and creates a risk of overheating and potential fires.

What does “SCCR” stand for? +

SCCR is short for “Short-circuit Current Rating”, the maximum current a device or system can safely withstand. This applies to all power components in a control panel. This is a request normally required by a device that must comply with UL508A. Although Thermolec does not comply with UL508A, we can still provide an SCCR rating for heaters.

How is the SCCR rating determined? +

The SCCR rating given for any heater is based on the lowest value of a component in the power circuit. If there are 4 components in the power circuit, the component with the lowest value is what determines the overall SCCR rating of the given heater.

Can any Humidistat be used to control an Acu-Steam? +

No, the humidistat must be a dry contact to enable/disable the humidifier. If the signal to the humidifier is 24VAC, a relay will need to be added to enable/disable the humidifier.

How often should an Acu-Steam be cleaned? +

Thermolec recommends that any Acu-Steam humidifier be cleaned at least twice per season. Refer to the maintenance guide for instructions. See Section 8 – Maintenance in the Acu-Steam Manual.

How often should the inlet water filter be changed on an Acu-Steam? +

Thermolec recommends that the inlet water filter be changed every 6 months to a year.

What if, after cleaning an Acu-Steam, error codes “3” and “4” still appear? +

Thermolec recommends purchasing and installing the Acu-Steam Maintenance/Tune-Up kit. If the installation is brand new, verify that the unit is properly installed as per the Acu-Steam User Installation Manual. Proper installation is critical to proper operation since the unit operation is dependant on gravity.

Can hot water be used to supply an Acu-Steam? +

No, using hot water to supply an Acu-Steam can cause harm to the operation of the unit.

Which setting is dipswitch #2 supposed to be in the CTH-291? +

Set the dipswitch #2 in the “RA” position for heating mode. “DA” is only for cooling mode.

What does the symbol “- - “mean on the display screen of the CTH-291? +

If the screen show “- - “, this means there is a disconnected or broken temperature sensor. This can either be the internal sensor when the CTH-291 is used as a room thermostat, or an external duct sensor connected to terminals 7 & 8 when used as a duct thermostat.

What do the symbols “LO” & “HI” mean on the display screen of the CTH-291? +

If you see either “LO” or “HI” appear on the display screen, this means that the temperature detected for operation is outside the operating scope of the CTH-291. “LO” means the ambient temperature is below -20°C (-4°F). “HI” means the ambient temperature is above 60°C (140°F).

If the screen on the CTH-291 is completely blank, what does that indicate? +

If the screen on the CTH-291 is completely blank upon startup, it most likely means that either there is no power connected to the thermostat, or the thermostat is defective. To function, 24VAC needs to be supplied to terminals R & C in the CTH-291.

Where is the best place to install the DS-600 sensor when using the CTH-291 as a duct thermostat? +

It is recommended that the DS-600 be placed the same dimension as the width of the duct (the heater’s “W” dimension) downstream from the heater for ideal operation.

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