Red Dragon 12m2 Motor block

[Twistedpro]

The motor block on my red dragon 12000 has failed and the replacement from royal exclusive is £334. I am not sure i want to pay that much for an old pump, although it has given me years of use.

The problem i have is the closed loop system the pump is running is all hard plumbed and i am very reluctant to plumb to fit a new pump and try and change the plumbing with the tank full.

I was aware that the laguna maxflow pumps use the same motor block. Is anyone aware whether its possible to swap the red dragon motor block for a laguna motorblock? Do you know what model laguna pump i would need?

 

[GQuinn]

The motor block on my red dragon 12000 has failed and the replacement from royal exclusive is £334. I am not sure i want to pay that much for an old pump, although it has given me years of use.

The problem i have is the closed loop system the pump is running is all hard plumbed and i am very reluctant to plumb to fit a new pump and try and change the plumbing with the tank full.

I was aware that the laguna maxflow pumps use the same motor block. Is anyone aware whether its possible to swap the red dragon motor block for a laguna motorblock? Do you know what model laguna pump i would need?

PM member "Slief". He is a rep for Royal exclusive and will tell you what Laguna block you will need.

 

[slief]

That pump block is a big block and likely has the AKB (Anti-lime Bypass) which is the tube connection that runs between the block and the Volute/pump head to keep the magnet cavity cooler. The off the shelf Maxflo/Askoll blocks will not work to replace that pump motor due to the AKB. If your pump doesn't have the AKB, even finding the correct Laguna pump with the big block motor in it is next to impossible as most have the smaller Askoll blocks. Plus there is a wide range of block speeds which complicates it even further making it next to impossible to find the correct generic block for that pump. Plus, RE has these Red Dragon pumps specially made by Askoll with special speeds for the impeller and flow.

My suggestion would be to replace the motor block with the one from Royal Exclusiv. For the cost of a replacement block, you will be hard pressed to find a more reliable pump for your closed loop that produces that much flow and does so that quietly. As you know from the amount of time you got out of that block, they are very reliable and great pumps. In fact, the only reason that block likely failed is due to calcium buildup on the bearing below the magnet where the impeller goes into the block. That or some other type of restriction that would have created some sort of resistance on the impeller. The bearing happens to be one of the most often overlooked and neglected maintenance items and without somewhat regular cleaning of the bearing and impeller, these pumps can fail prematurely. If you maintain the bearing and keep the impeller reasonably clean, these pumps will last well over 10 years if not indefinitely. That said, you might want to pull the pump apart, remove the bearing and clean it well. If the bearing is seized to the shaft or has calcium buildup in it, that will prevent the impeller from spinning. Prolonged resistance on the shaft from calcium build up or obstructions will overload the motor and potentially burn it out.

Take a look at page 6 of this manual for info on the bearing including removal of it and reinsertion. You need to clean it thoroughly inside and out.
http://royalexclusiv.net/images/content/rd_1/eng/rd1_operating_maintenance_eng.pdf

 

[Twistedpro]

Many thanks for your reply Slief, as you say the pumps are very reliable this one has run for 5 years. It has now started knocking and shaking when i try and run the pump. I will take it apart and clean the bearings to see if this is the cause of the pump vibrating like this.

If this does not help i will send the pump back to Royal Exclusive when they have finished the move

 

[slief]

Many thanks for your reply Slief, as you say the pumps are very reliable this one has run for 5 years. It has now started knocking and shaking when i try and run the pump. I will take it apart and clean the bearings to see if this is the cause of the pump vibrating like this.

If this does not help i will send the pump back to Royal Exclusive when they have finished the move

I would also double check the magnet and make sure it's still properly bonded to the impeller shaft. If the magnet is slipping on the shaft or if the bearing is tight from calcium buildup or if the bearing is stuck to the shaft, that would cause the issue you are experiencing. Generally when the blocks go bad, they will no longer run at all. My suspicion is that you might be pleasantly surprised what a deep cleaning might do.

 

[Twistedpro]

I will take a bottle of acetic acid home tonight and give everything a good soak. If the magnet is not bonded to the impeller shaft can this be fixed at home?

 

[slief]

I will take a bottle of acetic acid home tonight and give everything a good soak. If the magnet is not bonded to the impeller shaft can this be fixed at home?

Use vinegar and not acid. It shouldn't take a long soak so soften any cakium buildup. Soak it for 15 or minutes and give it a good scrub with a soft brush such as those used for dishes. Clean the end (bottom) of the impeller shaft with some scotch brite if necessary to make it clean and smooth.

If the magnet came loose from the impeller shaft which is unlikely, you could epoxy it in place but that requires knowing exactly where the magnet was on the shaft which could be easy to tell by the shaft coloring and or any marks from the magnet and taking a measurement from the base of the shaft to the bottom of the magnet. Then removing the magnet, cleaning the shaft well and then adding some epoxy to the shaft and inside of the magnet before sliding it back into the place. You will need to clean any excess glue/epoxy from the shaft.