Kerr comet 145 oil fired boiler

Diy69

I have the above heating system.  It has an internal heating coil for condumsble hot water. Lately I've been experiencing low to leas than normal flow to hot water taps including the showers. Reasonably normal water flow in mix position and cold but hf or less when turned towards and completely to hot. It'd not an easy task without actual knowledge to remove and replace hot water coil. I can separate the hot line at the temp control but the cold would have to be unsoldered or cut then remove the bolts for the coil. It is the original child which the system was installed 22 years ago. What's the procedure for removing the coil other than the two water connections and the mounting bolts.
Plus do you think my water flow is due to a plugged/calcified coil?
Thanks

EdTheHeaterMan

You may be able to clean that coil in place.

There are kits and systems that will clean tankless water heaters. you need to flush the coil with the cleaning agent from the kit using a continues flow from a pump drawing the cleaning fluid from a 5 gal pale, pumping thru the coil, then dumping the water from the coil back into the bucket.

Since you are ready to solder a new coil in place, you may as well solder the necessary valves into the coil you have and tru the cleaning idea first. Even if you decide to replace the coil with a new one, you can use the new valves to maintain your new coil, annually.

https://www.amazon.com/Chromex-Tankless-Heater-Descaler-Kit/dp/B08JH6W566/ref=sr_1_1_sspa?keywords=tankless+water+heater+cleaning+kit&qid=1671306038&sr=8-1-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUE3TE5FRk5IUDZPUVcmZW5jcnlwdGVkSWQ9QTA2NjQ2MTkyMjNXTUlJVTNFREtJJmVuY3J5cHRlZEFkSWQ9QTAzNDE4MTEzRTM3TjdNNlBHRElZJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1