E-boilers: frequently asked questions

We still get a lot of questions about our E-boilers from Varmeteknikk. Most questions are answered in the manual, which can be found in our download section. You will also find the answers to the most frequently asked questions below. A PDF of this document can be downloaded from this page.

Q: Is there an instruction manual available?

A: Yes; see Operating instructions SB 180 – 1200 kW

Q: Is there a neutral connection required?

A: No, not for the 400V connection. When connecting the boiler, you don’t need the zero conductor, so it’s best to use three-core cables. There is no place/clamps for connecting a zero conductor.

Q: Is a control voltage required?

A: Yes, for the temperature controller and boiler controls you need a separate external single phase 230 VAC / 50 Hz (1/P/N AC230V) supply.

Q: Can we tap into the high-power supply for the control voltage?

A: No, when you are performing maintenance on the boiler, you need to disconnect from the high-power supply. If you tap the control voltage into the busbars / high power, you will lose the control voltage, which you need for servicing as well.

Q: Can we use single core cables as well?

A: Yes, that is possible. But if you intend to pass multiple single core cables through one cable gland, please inform us and we will supply a better suitable cable gland plate (SS or Lexan) to avoid induction noise.

Q: Are there tightening torques?

A: Yes, the right tightening torques for the cables can be found in the manual; see Operating instructions SB 180 – 1200 kW.

Q: Is the connection box always on the right-hand side?

A: SB boilers are delivered with a connection box (or boxes ≥ 375 kW) for connecting the power cables. The connection box can be installed on the right- or left-hand side with cable entry from the top or from the bottom. As standard the boiler is prepared for right side connection. If you wish to install the connection box on the left side, please inform us when ordering.

For more information see manual: Operating instructions SB 180 – 1200 kW.

Q: Are there specification or restrictions for the water quality?

A: Yes, the most important values are:

- Ph-value between 8,5 – 9,0

- Alkalinity not more than 60 mg/l

- Carbonate content not more than 25 mg / l

- Chloride content not more than 100 mg / l

- Sulphate content not more than 60 mg / l

Water that is too hard or too soft can cause scale deposits and/or corrosion of the copper heating elements.

When in doubt, take a water sample or visually inspect the elements once or twice a year

Q: Is service needed?

A: Yes, to avoid unnecessary downtime, the boiler should be inspected annually. The inspection should include the following points:

- Check the boiler for leakage

- Control & check of elements

- Check contactors / relays

- Check electrical connections

- Check regulator function

- Check safety thermostat

For more information see manual: Operating instructions SB 180 – 1200 kW.

Q: Is there an error or troubleshooting list?

A: Yes, see manual: Operating instructions SB 180 – 1200 kW.

Q: Is there a spare part list?

A: Yes, see manual: Operating instructions SB 180 – 1200 kW.

Q: What are the heat losses? A: There is some radiant heat from the boiler itself, but that loss is limited due to the insulation package around and the low water content of the appliance.

Q: Is aeration of the boiler room required? A: Local requirements must be considered. The ventilation requirements must also be included in the general installation instructions of the building in which you place the boiler. Ventilation is necessary to limit the room temperature to prevent equipment damage and/or malfunctions. Room temperature, recommendation: min. 0 °C and max. 10 °C above the outside temperature if it rises above 30 °C

Q: How much free space around the boiler is required?

A: The required space around the boiler depends on its capacity and is described in the Operating instructions SB 180 – 1200 kW.

Q: Which protection class does the boiler have?

A: The boiler’s protection class is IP20.

Q: What water side safeties must be installed?

A: The manufacturer recommends installing 2 safety valves, as close as possible to the boiler and without shut-off valves between the overflows and the boiler. In addition, we recommend installing an extra minimum & maximum pressure safety device (presso switches) and a low water safety device (2x ¾” side connection) on the piping. An additional socket is fitted to the flange connection of the supply line for connecting an expansion vessel.

Q: How is the temperature controlled?

A: The boilers are equipped with an electronic temperature controller (PID). The supply temperature is adjustable between 5 – 95°C and the boiler controls are designed to keep a constant water temperature. The boiler is factory set to a flow temperature of 80°C and equipped with a built-in maximum temperature safety (110°C).

Q: How is the power switched up and down?

A: The boiler power is switched up in 7, 15 or 30 steps, depending on its capacity. The switch-up time per stage is adjustable between 1 and 250 seconds. By default, the switch-up time is set to 40 seconds, with 4 to 8 relays controlling the circuit breakers. When the system will switch up or down depends on the function of the boiler or how its temperature is controlled: for example, based on the outside temperature, available electrical energy, in conjunction with other boilers/CHPs, etc.

The switch-down time per stage is adjustable between 1 and 20 seconds and is set to 5 seconds by default.

ð Short switching up and down times will contribute to faster wear & aging of the elements.