how long do you use it for before this happens?
have you been lubricating the running belt?
Also how old is the machine?
About 20 mins
The machine is quite old but hardly been used
Have you ever changed the running belt/
No to lube and no to changing it
ah that will be the problem. When the belt gets worn, normally lasts about 3-4 years in a home it caused excessive power consumption especially when it hasn't bee lubricated.
The machine puts out too much power to compensate and causes the speed to change.
I suggest lubricating the belt first as it is cheap £10 for years supply and see if this resolves it which I would be pretty sure it will
ill just get you a hyper link for some on ebay
i have worked on a lot of horizon treadmills and they are great. but do need lubricating
also are you using it on an extension cord?
Ok thanks I will try that
that should resolve it. but if it is on an extension cord make sure it is plugged into the wall directly
if you need any further advice feel free to contact me