Thermostat on a Vokera Mynute 16e gas boiler

YFlyer

Hi there

I have a Vokera Mynute 16e gas boiler. Currently using it to heat the water in the hot water tank, not the radiators.

I'm trying to find out what temperature does the water heat by using the thermostat.

Are the different lengths of archs around the circumference depict different temperature settings?

Thanks.

YFlyer

Would there be a temperature difference with the water heated in the hot tank depending on how you set the thermostat at the gas boiler?

Thanks

10-10-20

https://www.boards.ie/discussion/2058254237/thermostat-on-a-vokera-mynute-16e-gas-boiler

No, it's not an indexed control. One segment does not indicate anything like 1 or 5 degrees C. The reason for this is that the losses between the boiler and the cylinder are unknown to the boiler, so the dial does not operate using a scale.

You just need to test the temperature at the tank or taps and then raise or lower the dial by a small margin each time.

10-10-20

https://www.boards.ie/discussion/comment/119331920#Comment_119331920

On mine, a 28e, it does. I have my dial set to around the same location as yours and mine heats to about 70 degrees C at the tank. Can't speak for yours, for the reasons mentioned above!

YFlyer

https://www.boards.ie/discussion/comment/119332564#Comment_119332564

Thank you.

The water would constantly heat in the hot water tank while the gas boiler is on?

YFlyer

https://www.boards.ie/discussion/comment/119332571#Comment_119332571

Do you have a temperature at the tank? Does the boiler switch off when the water in the tank reaches 70 C? I'm asking if the boiler was on for hours, would the water reach boiling point or plateau at 70C?

Thank You

YFlyer

https://www.boards.ie/discussion/comment/119332564#Comment_119332564

Sorry to annoy you again.

For the thermostat. The longer the arch, the longer the boiler flame the gas? It be independent of temperature of water in the hot water tank?

Have no thermometer at the hot water tank.

Thanks

10-10-20

https://www.boards.ie/discussion/comment/119333075#Comment_119333075

Yes, it would, but that would be wasteful. Normally you would have an external clock on the boiler, is that not present?

https://www.boards.ie/discussion/comment/119333094#Comment_119333094

There should be but on my tank there is no temp control (it's a slightly silly setup - previous owner's design). Mine heats up for 1hr10 each morning and at some point goes into a "plateau" mode. Yours will do the same if it was left on for hours as the boiler would seek to maintain the feed (out-flowing) water at 70 degrees C.

https://www.boards.ie/discussion/comment/119333589#Comment_119333589

No, that dial does not vary the flame height, it's just setting the target temperature of the feed water (out-flowing water).

The flame height will change over a heating cycle as you have what's callled a modulating boiler. That means that the boiler looks at the system pressure, flow and input & output temperature and compares this against the target temperature (as set by the dial). It then automatically modulates the flame to match the need.

You seem to be trying to troubleshoot a problem, what are you troubleshooting?

If you want to measure the set temperature you would be best off measuring the heat of the output pipe on a section of copper nearest the boiler while it's heating the tank. That would give you a rough indication as to what it's running at.

YFlyer

https://www.boards.ie/discussion/comment/119334099#Comment_119334099

I have a clock on the boiler to set the timer or put on constant. That clock?

Meant to say flame duration.

I will have to get a thermometer to check the tap water temperature. Feels uncomfortable on the hands when boiler is on for 1.5 hours. 70 C be stinging on the hands?

Thanks for your reply.

10-10-20

https://www.boards.ie/discussion/comment/119334224#Comment_119334224

Yes, that clock. Normally about an hour or so will bring the water up to temperature. But that changes in Winter when the incoming water is colder and there is more thermal loss in the house/hotpress.

Anything over ~60 degrees will sting or be uncomfortable to put your hand into. But you're recommended to have your hot water above 62 degrees C to prevent legionella from spreading, so it's a fine line. Is there a safety concern with kids or elderly and the existing hot-water or just a preference to have it less hot?

YFlyer

https://www.boards.ie/discussion/comment/119334356#Comment_119334356

Thanks. It is a preference to have the water less hot, especially when washing my face. Hot and cold taps in bathroom have two different spouts.

Much appreciated.

YFlyer

My troubleshooting is to determine if the gas boiler is on for a long period would the temperature start going over the 70C and head towards boiling point?

10-10-20

https://www.boards.ie/discussion/comment/119334448#Comment_119334448

No, the boiler will modulate and stop at the temperature indicated at the dial. There is little or no risk of the water getting up to a boiling point even if you also have the electrical element enabled as it also has a thermostat.

As I said, that isn't an indexed dial, so you need to play around with it to raise and lower the temperatures according to your preference.

I found with mine that if you picture the temperature control as a clock - the equivalent of 5 minutes of a change was about 5 degrees C of a difference, roughly speaking. So adjust the temperature back by the equivalent of 5 mins and that might lower the temperature by about 5 degrees, or there-abouts.

From the manual:

https://www.manualslib.com/manual/830306/Vokera-Mynute.html?page=5#manual

"The variable thermostat allows you to set the temperature of the water to your radiators and hot water cylinder (not the hot water to your taps!) between 40ºC (min) and 80ºC (max)."

"To adjust the output temperature of the appliance turn the thermostat knob clockwise to increase or anti-clockwise to decrease.

When the appliance reaches the set temperature, the burner will go off for minimum period of approximately 3 minutes."

YFlyer

https://www.boards.ie/discussion/comment/119334533#Comment_119334533

Thank you for your reply.

I'm currently only heating the water for the taps and showers. The radiators are not on these days. So no need to be concerned about the positioning of the variable thermostat?

I don't seem to have a dial that display any temperature. My boiler lay out is the following. (The photo in the OP was uploaded from a website).

If the hot water cylinder thermostat is functioning properly, I shouldn't be too concerned.

Thanks again.

10-10-20

I really think you need to read the manual. The "variable thermostat" is the control for the temperature of the water from the boiler. This is normally fed into either the radiators or into the cylinder to heat up the cylinder water (using a heat exchange called the cylinder coil). There is a direct relationship between the position of that dial and the target temperature of the water.

https://www.manualslib.com/manual/830306/Vokera-Mynute.html?page=3#manual

As long as you follow the guidance in the manual to adjust the temperatures to your liking, you'll be fine.

YFlyer

https://www.boards.ie/discussion/comment/119335128#Comment_119335128

Thanks. I must have been over tired last night thinking the variable thermostat only affects the water that goes to the radiators.

I forgot about the opening the valve next to the hot water tank to redirect the boiler water to the rads as well.