Can you run a combi boiler with heating drained?

Asked By: Nikolina Iannini | Last Updated: 23rd January, 2020
Category: home and garden home appliances
4.4/5 (956 Views . 26 Votes)
you do not need to isolate the cold water feed to the combi boiler ,when draining radiators. you can not use the boiler for domestic hot water whilst system is drained down. isolate electric supply to boiler before draining .

Click to see full answer


Besides, how do I drain my central heating with a combi boiler?

How to drain and repressurise a combi boiler system

  1. Before you begin. Turn off the boiler and disconnect it from the power supply.
  2. Locate the drainage valve. The drainage point in any system will usually be the lowest point of the lowest radiator in the property.
  3. Open the vents.
  4. Opening the filling loop.
  5. Check for leaks.
  6. Bleed the radiators.

Secondly, will turning water off affect combi boiler? Combi boilers take water directly from the mains, so if you need to switch your water off, this will affect your appliance. You can continue to use your heating while the water is switched off, but you must not use your hot taps at all. If you turn your hot taps on, you risk damaging your boiler.

Hereof, can I drain central heating and still have hot water?

no, the CH water is what warms the coil in the hot water tank. You might still be able to have hot water if you have an imersion heater though.

Can combi boilers heat water and radiators at the same time?

A combi boiler will usually need to pause from heating the central heating water for your radiators while it's heating the hot water for your tap, because they often can't supply enough heat to supply to both at the same time.

39 Related Question Answers Found

How long does it take to drain a boiler?

It almost takes 20-25 minutes to drain out entire water from the heater and executing the whole process. But this duration varies from the size of the heater. Ideally, with the flow rate between 9 GPM to 17 GPM, for a 5—gallon tank, if the water flows out in the full swing, the tank gets emptied within 6-7 minutes.

How do you bleed a radiator with a combi boiler?

Read on to find out in our step-by-step guide.
  1. Turn on the heating. The first step is to turn on your heating system.
  2. Check individual radiators. As soon as you're up to temperature, have a check of each of your individual radiators.
  3. Get bleeding!
  4. Bleeding a radiator with combi boilers.
  5. If you have steam radiators.

How do you flush out a boiler?

To flush the system, open the blow-off valve and let the water run off into a bucket until it runs clear. If the water still looks rusty after the system has been flushed, call a professional service person. Turn off power to boiler, and let water cool until it's just warm.

How do you drain a zone on a boiler?

How to Drain a Radiator
  1. Turn off all power to the boiler. The power switch will be located on the boiler.
  2. Turn off the gas to the boiler system.
  3. Shut off the water intake valve.
  4. Let the system cool down for at least 30 minutes.
  5. Locate the drain valve at the bottom of the boiler.
  6. Open the drain valve by turning it counter-clockwise.

How do you drain a vented central heating system?


How to drain a central heating system
  1. Switch off the boiler at the programmer.
  2. Solid Fuel Fire.
  3. Water Supply.
  4. Locate Drain Valve.
  5. Locate all the points at which air is vented from the central heating system.
  6. Open the drain valve with a spanner, pliers or an Isle of Man key, turning counter-clockwise.
  7. Start opening the venting points at the top of the system.

Will heating still work if I remove a radiator?

Removing a Radiator: Do I Drain the Whole System? The answer to this is yes and no -- but it's all good news – yes you don't have to drain the whole central heating system but no you don't even have to connect the two pipes together.

How does a combi heating system work?

Combi boilers work by having one compact system heating both your hot water and radiators so there is no need to have an additional external cold-water tank or hot water cylinder. As soon as you turn the hot water tap, the boiler will kick in and the water will become hot very quickly.

Can I just remove a radiator?

Depends if it is a one pipe or 2 pipe system, you need to find the pipe that the radiator is fed from. If it's a 2 pipe system then yes you can but if you are removing it permanently then you should really cap the pipe as close to the main feed pipes as possible.

How do you drain a central heating system without a drain valve?

The alternative way to draining the central heating system is, if you have no draining point, fit a draining point to the top of the radiator. When both radiator valves are in the off position. Once the draining point is in place, then attach the hosepipe and open draining valve including both radiator valves.

Will my boiler work without water?


If boilers didn't come with a host of sensors and controls, it might indeed damage your boiler if you turned it on with no water to heat up. Your combi boiler would be the worst affected, as the heat exchanger could suffer, but your cylinder and radiators would probably be fine.

Do you need to remove radiator before plastering?

4 Answers from MyBuilder Plasterers
The only way to get a good finish behind the radiators is to remove them and refit once your finished. even more so that you want to have the walls plastered, as theres just no way to get a trowle behine it.

Can I turn off the water and leave the heating on?

Leave Hot Water Off and Cold water mains off too. Leave heating on but turn it down from thermostat(what temp ??) We are worried about frozen pipes exploding and flooding our house, so please advise guys.

Should I turn my combi boiler off when I go on holiday?

One thing to note however, is that it's typically recommended that you do not switch your boiler off if you go on holiday during winter or cold spells, as your pipes could freeze and you could risk being faced with central heating issues when you get back.

Should you turn water off when going away?

The safest thing to do before you go away is to turn off the water supply completely. It might not stop water that's already in the pipes from escaping, but it will limit the risk of a flooded home.

Can you use your central heating when water is off?


Natural gas central heating systems should continue to operate in instances where water from the mains supply has been cut off.

Should I turn off hot water when on holiday?

It's not recommended to completely turn off a water heater, but you can a significant amount of energy—and money—while on vacation by switching the water heater to vacation mode. If your heater doesn't have vacation mode, simple lower the temperature several degrees to prevent it from cycling on and off so often.

Where is the hot water supply shut off?

If you have a combi boiler, you can turn off the hot water by turning off the mains stopcock. You can usually find the mains stopcock in the vicinity of the kitchen sink. It may be in the cupboard under the sink, or it may be on an adjacent pipe.